drm/xe: Move primary GT allocation from xe_tile_init_early to xe_tile_init

drm/xe: Move primary GT allocation from xe_tile_init_early to xe_tile_init

During the early days of the Xe driver, there were cases where we
accessed some fields in the primary GT's xe_gt structure before the GT
itself was formally initialized; this required that the structure itself
be allocated during xe_tile_init_early().  A lot of refactoring of the
device probe has happened since that time and there's no longer a need
to allocate the primary GT early.  Move the allocation into
xe_info_init() where GT initialization happens and where we're doing the
allocation of the media GT.

v2:
 - Only make this change after a separate patch to perform VF GMD_ID
   lookup with a dummy GT instead of xe_root_mmio_gt().

Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://lore.kernel.org/r/20251013200944.2499947-33-matthew.d.roper@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>