kgdb,arm: fix register dump

DBG_MAX_REG_NUM incorrectly had the number of indices in the GDB regs
array rather than the number of registers, leading to an oops when the
"rd" command is used in KDB.

Cc: stable@kernel.org
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>

arch/arm/kernel/kgdb.c

@@ -79,7 +79,7 @@ sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *task)
 		return;
 
 	/* Initialize to zero */
-	for (regno = 0; regno < DBG_MAX_REG_NUM; regno++)
+	for (regno = 0; regno < GDB_MAX_REGS; regno++)
 		gdb_regs[regno] = 0;
 
 	/* Otherwise, we have only some registers from switch_to() */