[PATCH] ppc32: Check return of ppc_sys_get_pdata before accessing pointer

Ensure that the returned pointer from ppc_sys_get_pdata is not NULL before we
start using it.  This handles any cases where we have variants of processors
on the same board with different functionality.

Signed-off-by: Kumar Gala <kumar.gala@freescale.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>