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/macaddr.c b/src/macaddr.c
index e5db8cf..6a1588d 100644
--- a/src/macaddr.c
+++ b/src/macaddr.c
@@ -25,7 +25,7 @@
  */
 
 /*! \file macaddr.c
- *  \brief MAC address utility routines
+ *  MAC address utility routines
  */
 
 #include "config.h"
@@ -35,7 +35,7 @@
 #include <stdlib.h>
 #include <unistd.h>
 
-/*! \brief Parse a MAC address from human-readable notation
+/*! Parse a MAC address from human-readable notation
  *  This function parses an ethernet MAC address in the commonly-used
  *  hex/colon notation (00:00:00:00:00:00) and generates the binary
  *  representation from it.
@@ -70,7 +70,7 @@
 #include <net/if_dl.h>
 #include <net/if_types.h>
 
-/*! \brief Obtain the MAC address of a given network device
+/*! Obtain the MAC address of a given network device
  *  \param[out] mac_out pointer to caller-allocated buffer of 6 bytes
  *  \param[in] dev_name string name of the network device
  *  \returns 0 in case of success; negative otherwise
@@ -114,7 +114,7 @@
 #include <netinet/in.h>
 #include <netinet/ip.h>
 
-/*! \brief Obtain the MAC address of a given network device
+/*! Obtain the MAC address of a given network device
  *  \param[out] mac_out pointer to caller-allocated buffer of 6 bytes
  *  \param[in] dev_name string name of the network device
  *  \returns 0 in case of success; negative otherwise