[Why]
We need to be able to specify slice width for DSC on aconnector

[How]
Getting slice width parameter from debugfs entry, if it is
a valid the value is set in connector's dsc preffered settings
structure. Which then overwrites dsc_cfg structure's parameters
if DSC is decided to be enabled. Works for both SST and MST.
Signed-off-by: NEryk Brol <eryk.brol@amd.com>
Signed-off-by: NMikita Lipski <mikita.lipski@amd.com>
Reviewed-by: NMikita Lipski <Mikita.Lipski@amd.com>
Acked-by: NEryk Brol <eryk.brol@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>