clk: qcom: gcc: Add voter clocks for MDSS rotator

MDSS rotator requires separate resource initialization,
add the voter clocks to support the same for MSM8937.

Change-Id: I7f89cdfbe1d3f24ee38410ee477329458d25c3f7
Signed-off-by: Jayant Shekhar <jshekhar@codeaurora.org>