drm/amd/display: Fully switch to dmub for all dcn21 asics

[Why]
On renoir usb-c port stops functioning on resume after f/w update.
New dmub firmware caused regression due to conflict with dmcu.
With new dmub f/w dmcu is superseded and should be disabled.

[How]
- Disable dmcu for all dcn21.

Check dmesg for dmub f/w version.
The old firmware (before regression):
[drm] DMUB hardware initialized: version=0x00000001
All other versions require this patch for renoir.

Bug: drm/amd#1735


Acked-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Tested-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Roman Li <Roman.Li@amd.com>