msm: kgsl: Improve IFPC performance

Improve the performance of IFPC by decreasing the
WPTR retry delay to 10 us and extending main
hysteresis to 300 us.

Change-Id: If33bf027113c3a392f46ce4c02eed3963cb31f54
Signed-off-by: Kyle Piefer <kpiefer@codeaurora.org>