msm: kgsl: Extend GMU idle timeout

Profiling results show that there are corner cases when
default 10ms timeout for GMU idle is not enough. As per
conversation with HW team we'll use 100ms timeout.

Signed-off-by: Oleg Perelet <operelet@codeaurora.org>
Change-Id: I47f8fa55a4139397b96a90046df36fee2e4553d9
Signed-off-by: Urvashi Agrawal <urvaagra@codeaurora.org>