[Why]
DCN 3.1.4 uses dmub not dmcu. Attempt to identify
dmcu firmware for dcn314 results in dm init error:
"Unsupported ASIC type"

[How]
Add dcn314 to the list of asics that don't require dmcu
Signed-off-by: NRoman Li <roman.li@amd.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Reviewed-by: NHarry Wentland <harry.wentland@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>