msm: kgsl: Disable guardpage for A5x and suppress pagefaults

Disable the guardpage workaround for A5x and instead
selectively suppress pagefaults. Suppress read pagefaults
that are likely caused due to UCHE overfetches. For this,
the fault address must be within the first 64 bytes of a
page and the fault page must be preceded by a valid allocation.

CRs-Fixed: 975293
Change-Id: I6a0995af3ab4129c6923726043c5f34c747641f9
Signed-off-by: Sushmita Susheelendra <ssusheel@codeaurora.org>