drm/xe: Split MCR initialization

The initialization order of GT topology, MCR, PAT and GuC HWconfig
as done today by native/PF driver, can't be followed as-is by the
VF driver, since fuse registers used in GT topology discovery will
be obtained by the VF driver from the GuC in HWconfig step.

While native/PF drivers need to program the HW PAT table prior to
loading the GuC, this requires only multicast writes support from
the MCR code, which could be initialized separately from the full
MCR support that requires the GT topology to setup steering data.

Split MCR initialization into two steps to avoid introducing VF
specific code paths. This also fixes duplicated spin_lock inits.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Zhanjun Dong <zhanjun.dong@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240530115814.1284-1-michal.wajdeczko@intel.com