The stack command now sends the printk output back to the mconsole client.
This is done by registering a special console for the mconsole driver.  This
receives all printk output.  Normally, it is ignored, but when a stack command
is issued, any printk output will be sent back to the client.

This will capture any printk output, whether it is stack output or not, since
we can't tell the difference.
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>