We need the SWITCH_FRAME_SIZE define on Book3S_32 now too.
So let's export it unconditionally.
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Alexander Graf <agraf@suse.de> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Avi Kivity <avi@redhat.com>