memshare: Disable memshare to prevent access cached memory

The memshare allotted region for diag client is allocated from
CMA can be allocated as a cacheable memory before memshare
allocation. Due to a hardware limitation on sdm845, the clean
eviction can happen to the same cacheable region which is
used by HLOS. Access to cached region which is MSA locked
results in XPU violation. The patch disables memshare driver
on sdm845 to avoid cacheing the memshare allotted region.

Change-Id: Ibedcee370106722b6cc66fd8bbe3fc6effe047a2
Signed-off-by: Manoj Prabhu B <bmanoj@codeaurora.org>