[PATCH] add_preferred_console() build fix

Move add_preferred_console out of CONFIG_PRINTK so serial console does the
right thing.

Signed-off-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>