drm/xe: Separate engine fuse handling into dedicated functions

drm/xe: Separate engine fuse handling into dedicated functions

The single function to handle fuse registers for all types of engines is
becoming a bit long and hard to follow (and we haven't even added the
compute engines yet).  Let's split it into dedicated functions for each
engine class.

v2:
 - Add note about BCS0 always being present.  (Bala)
 - Add forcewake assertion to read_copy_fuses.  (Bala)

Cc: Balasubramani Vivekanandan <balasubramani.vivekanandan@intel.com>
Reviewed-by: Balasubramani Vivekanandan <balasubramani.vivekanandan@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://lore.kernel.org/r/20230309005530.3140173-1-matthew.d.roper@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>