msm: sde: match rotator h/w ctx on sequence and session

Use both the session and sequence IDs from a rotation
request to identify previously processed rotator hardware
contexts instead of just the session id, and fix an issue
with the linked list insertion of internal rotation
contexts.

This allows the correct context to be selected during
subsequent operations if the session contains more than
a single rotation context at a time.

CRs-Fixed: 2056550
Change-Id: I2585a0450387a825ed347169c06459bffb43f0ab
Signed-off-by: Clarence Ip <cip@codeaurora.org>