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/gsm/gsm0411_utils.c b/src/gsm/gsm0411_utils.c
index 543775c..ef67930 100644
--- a/src/gsm/gsm0411_utils.c
+++ b/src/gsm/gsm0411_utils.c
@@ -45,7 +45,7 @@
 #define GSM411_ALLOC_SIZE	1024
 #define GSM411_ALLOC_HEADROOM	128
 
-/*! \brief Allocate a message buffer for use as TS 04.11 message
+/*! Allocate a message buffer for use as TS 04.11 message
  *  \returns allocated message buffer */
 struct msgb *gsm411_msgb_alloc(void)
 {
@@ -53,7 +53,7 @@
 				   "GSM 04.11");
 }
 
-/*! \brief Turn int into semi-octet representation: 98 => 0x89
+/*! Turn int into semi-octet representation: 98 => 0x89
  *  \param[in] integer value representing decimal number 0..99
  *  \returns BSC encoded as nibbles, swapped */
 uint8_t gsm411_bcdify(uint8_t value)
@@ -66,7 +66,7 @@
 	return ret;
 }
 
-/*! \brief Turn semi-octet representation into int: 0x89 => 98
+/*! Turn semi-octet representation into int: 0x89 => 98
  *  \param[in] value byte containing two BCD nibbles in revere order
  *  \returns integer representing decoded, re-ordered nibbles */
 uint8_t gsm411_unbcdify(uint8_t value)
@@ -83,7 +83,7 @@
 	return ret;
 }
 
-/*! \brief Generate 03.40 TP-SCTS
+/*! Generate 03.40 TP-SCTS
  *  \param[out] scts Caller-provided buffer to store SCTS (7 octets)
  *  \param[in] time to encode */
 void gsm340_gen_scts(uint8_t *scts, time_t time)
@@ -104,7 +104,7 @@
 #endif
 }
 
-/*! \brief Decode 03.40 TP-SCTS (into utc/gmt timestamp)
+/*! Decode 03.40 TP-SCTS (into utc/gmt timestamp)
  *  \param[in] scts SMS Center Time Stamp
  *  \return time in UTC time_t format */
 time_t gsm340_scts(uint8_t *scts)
@@ -204,7 +204,7 @@
 	return minutes;
 }
 
-/*! \brief decode validity period. return minutes
+/*! decode validity period. return minutes
  *  \param[in] sms_vpf Validity Period Format in 03.40 encoding
  *  \param[in] sms_vp Validity Period Information Element
  *  \returns validity period in minutes */
@@ -245,7 +245,7 @@
 	}
 }
 
-/*! \brief determine coding alphabet dependent on GSM 03.38 Section 4 DCS
+/*! determine coding alphabet dependent on GSM 03.38 Section 4 DCS
  *  \param[in] dcs Data Coding Scheme in 03.38 encoding
  *  \returns libosmogsm internal enum \ref sms_alphabet */
 enum sms_alphabet gsm338_get_sms_alphabet(uint8_t dcs)
@@ -285,7 +285,7 @@
 	return alpha;
 }
 
-/*! \brief generate a TPDU address field compliant with 03.40 sec. 9.1.2.5 
+/*! generate a TPDU address field compliant with 03.40 sec. 9.1.2.5 
  *  \param[out] oa caller-provided output buffer
  *  \param[in] oa_len caller-specified length of \a oa in bytes
  *  \param[in] type GSM340_TYPE_*
@@ -321,7 +321,7 @@
 	return len_in_bytes;
 }
 
-/*! \brief Prefix \ref msgb with a RP header
+/*! Prefix \ref msgb with a RP header
  *  \param msg Message Buffer containing message
  *  \param[in] rp_msg_type RP Message Type
  *  \param[in] rp_msg_ref RP Message Reference
@@ -341,7 +341,7 @@
 	return 0;
 }
 
-/*! \brief Prefix \ref msgb with a 04.08/04.11 CP header
+/*! Prefix \ref msgb with a 04.08/04.11 CP header
  *  \param msg Message Buffer containing message
  *  \param[in] proto Protocol
  *  \param[in] trans Transaction