[PATCH] ppc32: #ifdef out ALTIVEC specific code in __switch_to

#ifdef out an ALTIVEC specific tweak in __switch_to()

Signed-off-by: Marcelo Tosatti <marcelo.tosatti@cyclades.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>