[PATCH] ppx32: Fix uninitialized variable in set_preferred_console

This fixes an uninitialized variable warning in arch/ppc/kernel/setup.c,
and this time gcc is actually right, there is a path that could result
in offset being uninitialized.  Zero is a sane default in this instance.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>