drm/i915: Drop has_dp_mst from device info

No need to have this parameter in intel_device_info struct
as the requirement to support it is the DDI support.

As a side effect of the of removal this flag, it will not be printed
in dmesg during driver load anymore and developers will have to rely
on to check the macro and compare with platform being used and IP
versions of it.

Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220505193524.276400-6-jose.souza@intel.com