doxygen: enable AUTOBRIEF, drop \brief

Especially for short descriptions, it is annoying to have to type \brief for
every single API doc.

Drop all \brief and enable the AUTOBRIEF feature of doxygen, which always takes
the first sentence of an API doc as the brief description.

Change-Id: I11a8a821b065a128108641a2a63fb5a2b1916e87
diff --git a/src/bits.c b/src/bits.c
index fe92f93..45ac8e2 100644
--- a/src/bits.c
+++ b/src/bits.c
@@ -26,13 +26,13 @@
 
 /*! \addtogroup bits
  *  @{
- *  \brief Osmocom bit level support code
+ *  Osmocom bit level support code
  */
 
 /*! \file bits.c */
 
 
-/*! \brief convert unpacked bits to packed bits, return length in bytes
+/*! convert unpacked bits to packed bits, return length in bytes
  *  \param[out] out output buffer of packed bits
  *  \param[in] in input buffer of unpacked bits
  *  \param[in] num_bits number of bits
@@ -60,7 +60,7 @@
 	return outptr - out;
 }
 
-/*! \brief Shift unaligned input to octet-aligned output
+/*! Shift unaligned input to octet-aligned output
  *  \param[out] out output buffer, unaligned
  *  \param[in] in input buffer, octet-aligned
  *  \param[in] num_nibbles number of nibbles
@@ -87,7 +87,7 @@
 		out[i] = (in[i - 1] & 0xF) << 4;
 }
 
-/*! \brief Shift unaligned input to octet-aligned output
+/*! Shift unaligned input to octet-aligned output
  *  \param[out] out output buffer, octet-aligned
  *  \param[in] in input buffer, unaligned
  *  \param[in] num_nibbles number of nibbles
@@ -108,7 +108,7 @@
 		out[i] = (in[i] & 0xF) << 4;
 }
 
-/*! \brief convert unpacked bits to soft bits
+/*! convert unpacked bits to soft bits
  *  \param[out] out output buffer of soft bits
  *  \param[in] in input buffer of unpacked bits
  *  \param[in] num_bits number of bits
@@ -120,7 +120,7 @@
 		out[i] = in[i] ? -127 : 127;
 }
 
-/*! \brief convert soft bits to unpacked bits
+/*! convert soft bits to unpacked bits
  *  \param[out] out output buffer of unpacked bits
  *  \param[in] in input buffer of soft bits
  *  \param[in] num_bits number of bits
@@ -132,7 +132,7 @@
 		out[i] = in[i] < 0;
 }
 
-/*! \brief convert packed bits to unpacked bits, return length in bytes
+/*! convert packed bits to unpacked bits, return length in bytes
  *  \param[out] out output buffer of unpacked bits
  *  \param[in] in input buffer of packed bits
  *  \param[in] num_bits number of bits
@@ -174,7 +174,7 @@
 	return cur - out;
 }
 
-/*! \brief convert unpacked bits to packed bits (extended options)
+/*! convert unpacked bits to packed bits (extended options)
  *  \param[out] out output buffer of packed bits
  *  \param[in] out_ofs offset into output buffer
  *  \param[in] in input buffer of unpacked bits
@@ -199,7 +199,7 @@
 	return ((out_ofs + num_bits - 1) >> 3) + 1;
 }
 
-/*! \brief convert packed bits to unpacked bits (extended options)
+/*! convert packed bits to unpacked bits (extended options)
  *  \param[out] out output buffer of unpacked bits
  *  \param[in] out_ofs offset into output buffer
  *  \param[in] in input buffer of packed bits
@@ -221,7 +221,7 @@
 	return out_ofs + num_bits;
 }
 
-/*! \brief generalized bit reversal function
+/*! generalized bit reversal function
  *  \param[in] x the 32bit value to be reversed
  *  \param[in] k the type of reversal requested
  *  \returns the reversed 32bit dword
@@ -242,7 +242,7 @@
 	return x;
 }
 
-/*! \brief reverse the bit-order in each byte of a dword
+/*! reverse the bit-order in each byte of a dword
  *  \param[in] x 32bit input value
  *  \returns 32bit value where bits of each byte have been reversed
  *
@@ -257,7 +257,7 @@
 	return x;
 }
 
-/*! \brief reverse the bit order in a byte
+/*! reverse the bit order in a byte
  *  \param[in] x 8bit input value
  *  \returns 8bit value where bits order has been reversed
  *
@@ -272,7 +272,7 @@
 	return x;
 }
 
-/*! \brief reverse bit-order of each byte in a buffer
+/*! reverse bit-order of each byte in a buffer
  *  \param[in] buf buffer containing bytes to be bit-reversed
  *  \param[in] len length of buffer in bytes
  *