clk: qcom: Add voltage voting for MSM8996 GCC driver

Global Clock Controller(GCC) needs to vote for volatge level on
rail for the clock frequencies, so add voltage voting in GCC.
Also clean up clock flags and parent info for few clocks.

Change-Id: Ib4cc69afb32a7654bbdd98f2efff901729c4d3da
Signed-off-by: Odelu Kukatla <okukatla@codeaurora.org>