msm: sde: Add dynamic OT support for rotator REGDMA

Dynamic OT is applied before rotator operation to control QoS.
Since REGDMA cannot access QoS registers directly, rotator
driver needs to wait for rotator idle before changing any
OT settings.  Once new OT is applied, REGDMA can resume
queueing until OT changes again.

CRs-Fixed: 989206
Change-Id: I2fd07a957b0d8414c855fafcff7a2613695efff0
Signed-off-by: Alan Kwong <akwong@codeaurora.org>