msm: kgsl: Increase the wait timeout for context detachment

Increase the wait timeout for context detachment to 30s instead
of 10s. Large IB's can take longer than 10s to retire and if a
hang happens then recovering from the hang and completing the
long IB's will take much longer than 10s, bump this timer to
30s which should be sufficient for the context's commands to
retire even if hang happens.

Change-Id: I610186473208c574b0bcada0b62a7407ae171d37
Signed-off-by: Harshdeep Dhatt <hdhatt@codeaurora.org>