drm/i915/dp: Add compute routine for DP HDR Metadata Infoframe SDP

It stores computed dp hdr metadata infoframe sdp to infoframes.drm of
crtc state. It referenced intel_hdmi_compute_drm_infoframe().

While computing, we'll also fill out the infoframes.enable bitmask
appropriately.

v2: Wrap a long line.
v4: Use struct drm_device logging macros
v5: Fix typo [Uma]

Signed-off-by: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200211074657.231405-4-gwan-gyeong.mun@intel.com