disp: msm: sde: return proper errno when register event fails

When HW resource is not available, return ENODEV so that user space can
check the errno and do proper handling.

Change-Id: If5422f1020c262ede4ac7226a274da2c5713b446
Signed-off-by: Ping Li <[email protected]>

msm/sde/sde_color_processing.c

@@ -4124,7 +4124,7 @@ int sde_cp_ltm_wb_pb_interrupt(struct drm_crtc *crtc, bool en,
 	hw_dspp = sde_crtc->mixers[0].hw_dspp;
 	if (!hw_dspp) {
 		DRM_ERROR("invalid dspp\n");
-		return -EINVAL;
+		return -ENODEV;
 	}
 
 	if (en) {