msm: kgsl: Increase the fenced write timeout

Make the fenced register write timeout twice as long
to increase the chances of success. Print a message
after half the time and after the full time to aid
in debugging.

Change-Id: I2cf87acacd40693046962031c598062c8b6bec84
Signed-off-by: Deepak Kumar <dkumar@codeaurora.org>