drm/msm/sde: support vbif memory type settings

The SMMU does not respect cache operation meta signals
unless the memory type is flagged to be cacheable. This
patch adds support for specifying the xin memory type
from the device tree.

CRs-Fixed: 2048687
Change-Id: I19eaba1738f08bd1d054977ffde80caeabd976b4
Signed-off-by: Clarence Ip <cip@codeaurora.org>