drm/amd/display: Add missing reg mask for dcn3

This field is missing for dcn3 so add it from dcn20.

enc2_set_dynamic_metadata() trys to sets this and we get a
generic_reg warning since the mask is not defined.
Signed-off-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn30/dcn30_dio_stream_encoder.h

@@ -248,6 +248,7 @@
 	SE_SF(DIG0_HDMI_METADATA_PACKET_CONTROL, HDMI_METADATA_PACKET_ENABLE, mask_sh),\
 	SE_SF(DIG0_HDMI_METADATA_PACKET_CONTROL, HDMI_METADATA_PACKET_LINE_REFERENCE, mask_sh),\
 	SE_SF(DIG0_HDMI_METADATA_PACKET_CONTROL, HDMI_METADATA_PACKET_LINE, mask_sh),\
+	SE_SF(DIG0_DIG_FE_CNTL, DOLBY_VISION_EN, mask_sh),\
 	SE_SF(DP0_DP_PIXEL_FORMAT, DP_PIXEL_COMBINE, mask_sh),\
 	SE_SF(DP0_DP_SEC_FRAMING4, DP_SST_SDP_SPLITTING, mask_sh),\
 	SE_SF(DIG0_DIG_CLOCK_PATTERN, DIG_CLOCK_PATTERN, mask_sh)