This commit helps to enable modifier support in mutter for i915 systems except some of the older and lower configurations for multimonitor use cases. The idea behind this commit is to enable modifier support on the latest i915 systems, Until we have TEST_ONLY commit to make sure to find the right modifier configuration for multi monitor use cases.
Related Issues:#1618 (closed) & #1623 cc: @jadahl @swick @kwg @mdnavare @shankaru