disas/ppc.c: Fix little endian disassembly

Use info->endian to select the endian of the instruction to
be disassembled.

Signed-off-by: Anton Blanchard <anton@samba.org>
Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>