drm/xe/xe_late_bind_fw: Fix and simplify parsing user input

drm/xe/xe_late_bind_fw: Fix and simplify parsing user input

Code was wrongly passing sizeof(uval) as the number base to use,
and unlike other debugfs entries that represent bool data, it
wasn't using the dedicated function to parse user input as bool.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Badal Nilawar <badal.nilawar@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
Link: https://lore.kernel.org/r/20251002192736.203186-1-michal.wajdeczko@intel.com