drm/xe/xe_survivability: Remove unused index

drm/xe/xe_survivability: Remove unused index

Remove unused index variable and fix for loop.

Fixes: f4e9fc967afd ("drm/xe/xe_survivability: Redesign survivability mode")
Reported-by: Nathan Chancellor <nathan@kernel.org>
Closes: https://lore.kernel.org/intel-xe/20251210075757.GA1206705@ax162/
Signed-off-by: Riana Tauro <riana.tauro@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patch.msgid.link/20251218105151.586575-5-riana.tauro@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>