drm/amd/display: Enabled pipe harvesting in dcn30

[Why & How]
Ported logic from dcn21 for reading in pipe fusing to dcn30.
Supported configurations are 1 and 6 pipes. Invalid fusing
will revert to 1 pipe being enabled.

Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Dillon Varone <dillon.varone@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Eryk Brol <eryk.brol@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>