drm/msm/dsi: drop mmss_cc.xml.h

The mmss_cc.xml.h file describes bits of the MMSS clock controller on
APQ8064 / MSM8960 platforms. They are not used by the driver and do not
belong to the DRM MSM driver. Drop the file.

Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/585843/
Link: https://lore.kernel.org/r/20240401-fd-xml-shipped-v5-3-4bdb277a85a1@linaro.org