clk: qcom: Add SDM660 Multimedia Clock Controller (MMCC) driver

Add a driver for the multimedia clock controller found on SDM660
based devices. This should allow most multimedia device drivers
to probe and control their clocks.

Signed-off-by: Martin Botka <martin.botka@somainline.org>
Co-developed-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Signed-off-by: Konrad Dybcio <konrad.dybcio@somainline.org>
[angelogioacchino.delregno@somainline.org: Cleaned up SDM630 clock fixups]
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org>
Link: https://lore.kernel.org/r/20210113183817.447866-4-angelogioacchino.delregno@somainline.org
[sboyd@kernel.org: Silence NULL pointer sparse warnings]
Signed-off-by: Stephen Boyd <sboyd@kernel.org>