ensure we don't use bootconsoles after init has been released

ensure we don't use bootconsoles after init has been released

This is a followup to the cleanups for earlyprintk patch from Gerd Hoffmann

http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=3804c260694314db440e50fc8ee32fb720b3cea6

This ensures that a bootconsole is unregistered if it is not replaced.
The current implementation spews garbage out the bootconsole in this case,
since the bootconsole structure is normally in the init section, and is
freed, but still used.

Signed-off-by: Robin Getz <rgetz@blackfin.uclinux.org>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Cc: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>