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/comp128v23.c b/src/gsm/comp128v23.c
index bfb4a0e..1797ebc 100644
--- a/src/gsm/comp128v23.c
+++ b/src/gsm/comp128v23.c
@@ -33,7 +33,7 @@
  */
 
 /*! \file comp128v23.c
- *  \brief COMP128 v2 / v3; Common Algorithm used for GSM Authentication (A3/A8)
+ *  COMP128 v2 / v3; Common Algorithm used for GSM Authentication (A3/A8)
  */
 
 static const uint8_t table0[256] = {
@@ -109,7 +109,7 @@
 	}
 }
 
-/*! \brief Perform COMP128v3 algorithm
+/*! Perform COMP128v3 algorithm
  *  \param[in] ki Secret Key K(i) of subscriber
  *  \param[in] rand Random Challenge
  *  \param[out] sres user-supplied buffer for storing computed SRES value
@@ -161,7 +161,7 @@
 	return 0;
 }
 
-/*! \brief Perform COMP128v2 algorithm
+/*! Perform COMP128v2 algorithm
  *  \param[in] ki Secret Key K(i) of subscriber
  *  \param[in] rand Random Challenge
  *  \param[out] sres user-supplied buffer for storing computed SRES value