Revert "drm/i915/color: Extract icl_read_luts()"

This reverts commit 84af7649.

This is causing problems with the display, displays are all
bright colors.

Fixes: 84af7649 ("drm/i915/color: Extract icl_read_luts()")
Signed-off-by: Swati Sharma <swati2.sharma@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190924135820.11850-1-swati2.sharma@intel.com