msm: kgsl: Reduce active context timer from 500ms to 100ms

Reduce the active context time from 500ms to 100ms, 500ms
seems to be a larger value for tracking active contexts
seen for the command queue.

Change-Id: I258e162b179451fa1f7774e0cc29a1e8be56195e
Signed-off-by: Prakash Kamliya <pkamliya@codeaurora.org>