clk: qcom: Add display clock controller driver for SM6115

Add support for the display clock controller found in SM6115/SM4250
based devices. This clock controller feeds the Multimedia Display
SubSystem (MDSS).
This driver is based upon one submitted for QCM2290.

Signed-off-by: Adam Skladowski <a39.skl@gmail.com>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20220911164635.182973-3-a39.skl@gmail.com