We have intel_rotation_90_or_270() in i915 to check if the rotation is
90 or 270 degrees. Similar checks are elsewhere in drm, so let's move
the helper into a central place and use it everwhere.

v2: Drop the BIT()
    Convert all new intel_rotation_90_or_270() calls
    Deal with superfluous code shuffling
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> (v1)
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1474907460-10717-2-git-send-email-ville.syrjala@linux.intel.com