drm/xe/xe3: Generate and store the L3 bank mask

drm/xe/xe3: Generate and store the L3 bank mask

On Xe3, the register used to indicate which L3 banks are enabled on
the system is a new one called MIRROR_L3BANK_ENABLE. Each bit
represents one bank enabled in each node.
Extend the existing topology code for Xe3 to read this register and
generate the correct L3 bank mask, which can be read by user space
throug the topology query.

Bspec: 72573, 73439
Signed-off-by: Francois Dugast <francois.dugast@intel.com>
Signed-off-by: Matt Atwood <matthew.s.atwood@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250114203853.35055-1-matthew.s.atwood@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>