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/conv.c b/src/conv.c
index b81e37e..38ce173 100644
--- a/src/conv.c
+++ b/src/conv.c
@@ -24,7 +24,7 @@
 
 /*! \addtogroup conv
  *  @{
- *  \brief Osmocom convolutional encoder and decoder
+ *  Osmocom convolutional encoder and decoder
  */
 
 /*! \file conv.c */
@@ -78,7 +78,7 @@
 /* Encoding                                                                 */
 /* ------------------------------------------------------------------------ */
 
-/*! \brief Initialize a convolutional encoder
+/*! Initialize a convolutional encoder
  *  \param[in,out] encoder Encoder state to initialize
  *  \param[in] code Description of convolutional code
  */
@@ -198,7 +198,7 @@
 	return o_idx;
 }
 
-/*! \brief All-in-one convolutional encoding function
+/*! All-in-one convolutional encoding function
  *  \param[in] code description of convolutional code to be used
  *  \param[in] input array of unpacked bits (uncoded)
  *  \param[out] output array of unpacked bits (encoded)
@@ -593,7 +593,7 @@
 	return min_ae;
 }
 
-/*! \brief All-in-one convolutional decoding function
+/*! All-in-one convolutional decoding function
  *  \param[in] code description of convolutional code to be used
  *  \param[in] input array of soft bits (coded)
  *  \param[out] output array of unpacked bits (decoded)