drm/i915: add FBC_ROTATION to enum no_fbc_reason

Because we're currently using FBC_UNSUPPORTED_MODE for two different
cases.

This commit will also allow us to write the next one without hiding
information from the user.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_fbc.c

@@ -587,7 +587,7 @@ void intel_fbc_update(struct drm_device *dev)
 	}
 	if (INTEL_INFO(dev)->gen <= 4 && !IS_G4X(dev) &&
 	    crtc->primary->state->rotation != BIT(DRM_ROTATE_0)) {
-		if (set_no_fbc_reason(dev_priv, FBC_UNSUPPORTED_MODE))
+		if (set_no_fbc_reason(dev_priv, FBC_ROTATION))
 			DRM_DEBUG_KMS("Rotation unsupported, disabling\n");
 		goto out_disable;
 	}