msm: kgsl: Add quirk for masking out hang detect signals

Add a quirk to mask out the RB 1-3 activity signals in the hang
detection logic. Set this quirk in the devicetree for 8996v2 and
v3.

CRs-Fixed: 978849
Change-Id: I63073b5973644453e775b41a9361de55d7933a07
Signed-off-by: Shrenuj Bansal <shrenujb@codeaurora.org>