clk: qcom: Add graphics clock controller driver for SC7180

Add support for the graphics clock controller found on SC7180
based devices. This would allow graphics drivers to probe and
control their clocks.

Signed-off-by: Taniya Das <tdas@codeaurora.org>
Link: https://lkml.kernel.org/r/1577428714-17766-4-git-send-email-tdas@codeaurora.org


Signed-off-by: Stephen Boyd <sboyd@kernel.org>