drm/i915/adl_p: MBUS programming

Update MBUS_CTL register if the 2 mbus can be joined as per the current
DDB allocation and active pipes, also update hashing mode and pipe
select bits as  per the sequence mentioned in the bspec.

Cc: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Cc: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Vandita Kulkarni <vandita.kulkarni@intel.com>
Signed-off-by: Clinton Taylor <Clinton.A.Taylor@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210519000625.3184321-10-lucas.demarchi@intel.com