Added arbel.c

src/include/gpxe/errfile.h

 #define ERRFILE_via_velocity	     ( ERRFILE_DRIVER | 0x00450000 )
 #define ERRFILE_w89c840		     ( ERRFILE_DRIVER | 0x00460000 )
 #define ERRFILE_ipoib		     ( ERRFILE_DRIVER | 0x00470000 )
-#define ERRFILE_mt25218		     ( ERRFILE_DRIVER | 0x00480000 )
 
 #define ERRFILE_scsi		     ( ERRFILE_DRIVER | 0x00700000 )
+#define ERRFILE_arbel		     ( ERRFILE_DRIVER | 0x00710000 )
 
 #define ERRFILE_aoe			( ERRFILE_NET | 0x00000000 )
 #define ERRFILE_arp			( ERRFILE_NET | 0x00010000 )