msm: rotator: Replace clk_set_min_rate() with clk_set_rate()

The rotator driver requests exact rates.  There is no need to call
the clk_set_min_rate() API, which will soon be removed altogether.
Call clk_set_rate() instead.

Change-Id: Ica9cb30f85132e92a00b0000eea498c47645b697
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>