drm/msm: don't allocate pages from the MOVABLE zone

The pages backing the GEM objects are kept pinned in place as
long as they are alive, so they must not be allocated from the
MOVABLE zone. Blocking page migration for too long will cause
the VM subsystem headaches and will outright break CMA, as a
few pinned pages in CMA will lead to failure to find the
required large contiguous regions.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Rob Clark <robdclark@chromium.org>