drm: Do not use bitwise OR to set picure_aspect_ratio

enum hdmi_picture_aspect is not a bitmask, so don't use bitwise OR
to populate it.

Cc: Ilia Mirkin <imirkin@alum.mit.edu>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190620142639.17518-2-ville.syrjala@linux.intel.comReviewed-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/drm_modes.c

@@ -1966,16 +1966,16 @@ int drm_mode_convert_umode(struct drm_device *dev,
 
 	switch (in->flags & DRM_MODE_FLAG_PIC_AR_MASK) {
 	case DRM_MODE_FLAG_PIC_AR_4_3:
-		out->picture_aspect_ratio |= HDMI_PICTURE_ASPECT_4_3;
+		out->picture_aspect_ratio = HDMI_PICTURE_ASPECT_4_3;
 		break;
 	case DRM_MODE_FLAG_PIC_AR_16_9:
-		out->picture_aspect_ratio |= HDMI_PICTURE_ASPECT_16_9;
+		out->picture_aspect_ratio = HDMI_PICTURE_ASPECT_16_9;
 		break;
 	case DRM_MODE_FLAG_PIC_AR_64_27:
-		out->picture_aspect_ratio |= HDMI_PICTURE_ASPECT_64_27;
+		out->picture_aspect_ratio = HDMI_PICTURE_ASPECT_64_27;
 		break;
 	case DRM_MODE_FLAG_PIC_AR_256_135:
-		out->picture_aspect_ratio |= HDMI_PICTURE_ASPECT_256_135;
+		out->picture_aspect_ratio = HDMI_PICTURE_ASPECT_256_135;
 		break;
 	default:
 		out->picture_aspect_ratio = HDMI_PICTURE_ASPECT_NONE;