msm: kgsl: allow creation of events from the future

For contexts created with the KGSL_CONTEXT_USER_GENERATED_TS,
allow events to be created for timestamps that have not
been issued yet. Presumably these contexts know what they
are doing.

Change-Id: Iccf2e549b38e1a11850d26ee64b7279ab0b8a1ae
Signed-off-by: Jeremy Gebben <jgebben@codeaurora.org>
msm: kgsl: Ensure that power constraints run for a full interval

Make sure that a power constraint is given a full DCVS interval to
influence the GPU before having it adjusted back down.

Change-Id: Ic0dedbad22e74ce6e62e26c386b900442d7bab40
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>