msm: kgsl: Increase GMU idle timeout to 100ms.

As per profiling there are cases when GMU timeout is taking more
than 10ms. Increase tieout to 100ms. This increase covers corner cases
and is not affecting general performance

Signed-off-by: Oleg Perelet <operelet@codeaurora.org>
Change-Id: I7d6c07a0b6e780d6b4d4cce84ea70b492583bde4