drm/xe/uc: Add support for different firmware files on each GT

The different GTs on a device can be very different. Right now for all
platforms the same firmware is loaded in each GT, however future
platforms may benefit from loading a different file depending on the GT
type.

Based on previous patch by John Harrison <John.C.Harrison@Intel.com>.

Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250307-xe-per-gt-fw-v1-2-459574d76400@intel.com


Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>