sysrq: add enable_mask in sysrq_moom_op

It is written in the Documentation/sysrq.txt that oom-killer is enabled
when we set "64" in /proc/sys/kernel/sysrq:

<Documentation/sysrq.txt>

    Here is the list of possible values in /proc/sys/kernel/sysrq:
         64 - enable signalling of processes (term, kill, oom-kill)
                                                          ^^^^^^^^

but enable_mask is not set in sysrq_moom_op.
Signed-off-by: Naohiro Ooiwa <nooiwa@miraclelinux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/char/sysrq.c

@@ -326,6 +326,7 @@ static struct sysrq_key_op sysrq_moom_op = {
 	.handler	= sysrq_handle_moom,
 	.help_msg	= "Full",
 	.action_msg	= "Manual OOM execution",
+	.enable_mask	= SYSRQ_ENABLE_SIGNAL,
 };
 
 static void sysrq_handle_kill(int key, struct tty_struct *tty)