drm/xe: Fix total initialization in xe_ggtt_print_holes()

drm/xe: Fix total initialization in xe_ggtt_print_holes()

Clang warns (or errors with CONFIG_DRM_WERROR or CONFIG_WERROR):

  drivers/gpu/drm/xe/xe_ggtt.c:810:3: error: variable 'total' is uninitialized when used here [-Werror,-Wuninitialized]
    810 |                 total += hole_size;
        |                 ^~~~~
  drivers/gpu/drm/xe/xe_ggtt.c:798:11: note: initialize the variable 'total' to silence this warning
    798 |         u64 total;
        |                  ^
        |                   = 0
  1 error generated.

Move the zero initialization of total from
xe_gt_sriov_pf_config_print_available_ggtt() to xe_ggtt_print_holes() to
resolve the warning.

Fixes: 136367290ea5 ("drm/xe: Introduce xe_ggtt_print_holes")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240823-drm-xe-fix-total-in-xe_ggtt_print_holes-v1-1-12b02d079327@kernel.org
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>