drm/xe: Move register MMIO into xe_tile

drm/xe: Move register MMIO into xe_tile

Each tile has its own register region in the BAR, containing instances
of all registers for the platform.  In contrast, the multiple GTs within
a tile share the same MMIO space; there's just a small subset of
registers (the GSI registers) which have multiple copies at different
offsets (0x0 for primary GT, 0x380000 for media GT).  Move the register
MMIO region size/pointers to the tile structure, leaving just the GSI
offset information in the GT structure.

Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://lore.kernel.org/r/20230601215244.678611-7-matthew.d.roper@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>