drm/xe: Fix size of xe_eu_mask_t

XE_MAX_DSS_FUSE_REGS was being used to calculate the size of
xe_eu_mask_t while it should use XE_MAX_EU_FUSE_REGS.
There are no know issues about this but fixing it anyways.

Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>