msm: kgsl: Go back to use REG_TO_MEM for the always on counter

While RECORD_PFP_TIMESTAMP seemed like a good idea at the time it
turns out that the timestamp gets recorded immediately in the PFP
(rather than the ME) so it really only tracks how quickly the
PFP can fetch the IB opcodes. Since this isn't the intent of
the feature go back to REG_TO_MEM to record the timestamp.
REG_TO_MEM is sent to the ME so it won't be executed until after
the command has completed.

Change-Id: Ic0dedbad463c846f4a1440738f13573fa9d90359
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>