isl: Use bpb for determining YUV image padding

When we initially dropped bpb in favor of bs, we accidentally didn't change
this one line properly.  This brings it back to what it should be.

Reviewed-by: Chad Versace <chad.versace@intel.com>

src/intel/isl/isl.c

@@ -996,7 +996,7 @@ isl_apply_surface_padding(const struct isl_device *dev,
     *      padding requirements.
     */
    if (isl_format_is_yuv(info->format) &&
-       (fmtl->bs == 96 || fmtl->bs == 48|| fmtl->bs == 24)) {
+       (fmtl->bpb == 96 || fmtl->bpb == 48|| fmtl->bpb == 24)) {
       *total_h_el += 1;
       *pad_bytes += 16;
    }