Allow admin to enable only some of the Magic-Sysrq functions.  This allows
admin to disable sysrq functions he considers dangerous (e.g.  sending kill
signal, remounting fs RO) while keeping the possibility to use the others
(e.g.  debug deadlocks by dumps of processes etc.).
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>