doxygen: score: adjust doc in mppkt.h to doxygen guidelines

Update #3706.

cpukit/include/rtems/score/mppkt.h

@@ -1,6 +1,8 @@
 /**
  * @file
  *
+ * @ingroup RTEMSScoreMPPacket
+ *
  * @brief Specification for the Packet Handler
  *
  * This package is the specification for the Packet Handler.
@@ -35,11 +37,14 @@ extern "C" {
  *
  * @ingroup RTEMSScore
  *
+ * @brief MP Packte Handler
+ *
  * This handler encapsulates the primary definition of MPCI packets.  This
  * handler defines the part of the packet that is common to all remote
  * operations.
+ *
+ * @{
  */
-/**@{*/
 
 /**
  *  The following enumerated type defines the packet classes.
@@ -111,7 +116,7 @@ typedef struct {
 #define MP_PACKET_MINIMUN_HETERO_CONVERSION  \
   ( sizeof( MP_packet_Prefix ) / sizeof( uint32_t   ) )
 
-/**@}*/
+/** @} */
 
 #ifdef __cplusplus
 }