msm: kgsl: Add an align mask property in the device tree

Add an alignment mask property in the DT to distinguish between
secure allocation requirements for different targets. For example,
8994 requires secure allocations to be 1M aligned, whereas
8996 has no such restriction.

Change-Id: I7d812057b4069616ca052e60b69c33df5ffdc453
Signed-off-by: Shrenuj Bansal <shrenujb@codeaurora.org>