[PATCH] ppc64: Fix CONFIG_ALTIVEC not set

The code that sets the altivec capability of the CPU based on firmware
informations can enable altivec when the kernel has CONFIG_ALTIVEC
disabled.  This results in "interesting" crashes.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>