drm/i915: Reject 90/270 degree rotated initial fbs

We don't currently handle the initial fb readout correctly
for 90/270 degree rotated scanout. Reject it.

Cc: stable@vger.kernel.org
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201020194330.28568-1-ville.syrjala@linux.intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>