gpu: ipu-v3: allow to build with COMPILE_TEST

Add missing include <linux/sizes.h> in ipu-cpmem and ipu-ic, select
BITREVERSE for ipu-cpmem and GENERIC_ALLOCATOR for ipu-pre, and allow
to build if COMPILE_TEST is enabled.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>