[PATCH] uml: capture printk output for mconsole sysrq

Pass sysrq output back to the mconsole client using the mechanism
introduced for stack output.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>