drm: Rename HDMI colorspace property creation function

As between HDMI and DP have different colorspaces, in order to distinguish
colorspace of DP and HDMI, it renames drm_mode_create_colorspace_property()
function to drm_mode_create_hdmi_colorspace_property() function for HDMI
connector.
In order to apply changed drm api, i915 driver has channged.

It addresses review comments from Ville.
 - Split hunk into renaming and adding of code.

Signed-off-by: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190919195311.13972-4-gwan-gyeong.mun@intel.com