msm: kgsl: Make sure RBBM_INT_0_STATUS is not transitory

In the interrupt handler, read the STATUS register for up to
3 times to see if the STATUS bits are not changing. This
is done in order to avoid handling the transitory bits.
Empirical data has shown that the transitory bits vanish
in the small window between two or three consecutive reads
of the register.

Change-Id: Ic7ef241d62ff2dc60f9427531d02381c396795b0
Signed-off-by: Harshdeep Dhatt <hdhatt@codeaurora.org>