msm: sde: Force setting SDE rotator clock even rate is the same

Due to a HW issue on the multimedia block on MSMCOBALT, the clock
sources or RCGs can end up running at XO frequency after a
multimedia power collapse. In order to avoid this issue, SDE rotator
as a multimedia clients need to call clk_set_rate() prior to
enabling its clocks.

CRs-Fixed: 1090358
Change-Id: Ib00b894f44a349fb3650df43f73f3599c09e46de
Signed-off-by: Benjamin Chan <bkchan@codeaurora.org>