drm/xe: Introduce xe_tile_init_early and use at earlier point in probe

It also merges the GT (which is part of tile) initialization happening
at xe_info_init with allocating other per-tile data structures into a
common helper function.

Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>