drm/i915/display/xelpd: Fix incorrect color capability reporting

On XELPD platforms, color management support is not yet enabled.
Fix wrongly reporting the same through platform info, which was
resulting in incorrect initialization and usage.

Cc: Swati Sharma <swati2.sharma@intel.com>
Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Reviewed-by: Swati Sharma <swati2.sharma@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210707095253.23848-1-uma.shankar@intel.com