drm/i915/mtl: Fix HDMI/DP PLL clock selection

drm/i915/mtl: Fix HDMI/DP PLL clock selection

Select the HDMI specific PLL clock only for HDMI outputs.

Fixes: 62618c7f117e ("drm/i915/mtl: C20 PLL programming")
Cc: Mika Kahola <mika.kahola@intel.com>
Cc: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Reviewed-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231213220526.1828827-1-imre.deak@intel.com
(cherry picked from commit 937d02cc79c6828fef28a4d80d8d0ad2f7bf2b62)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>