msm: kgsl: Fix throttle control register write value

Correct the value that is written to the GPMU clock
throttle control to account for newer revisions of the
hardware.

Change-Id: I87165c1a7c24dcd5eb42fe99e5cdf7d327b12765
Signed-off-by: Carter Cooper <ccooper@codeaurora.org>
Signed-off-by: Oleg Perelet <operelet@codeaurora.org>