drm/i915: Move the cursor rotation handling into intel_cursor_check_surface()

drm/i915: Move the cursor rotation handling into intel_cursor_check_surface()

Unlike other planes the cursor currently handles 180 degree rotation
adjustment during the hardware programming phase. Let's move that
stuff into intel_cursor_check_surface() to match how we do things
with other plane types.

And while at we'll plop in the final src x/y coordinates (which will
actually always be zero) into the src rect and color_plane[0].x/y,
just for some extra consistency.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191015152757.12231-1-ville.syrjala@linux.intel.com
Reviewed-by: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>