libbpf-tools: Don't print CPU frequency if count is zero
Count value zero means no such CPU frequency is captured, stop printing
it.
@@ -973,6 +973,8 @@ void print_linear_hist(unsigned int *vals, int vals_size, unsigned int base,
printf(" %-13s : count distribution\n", val_type);
for (i = idx_min; i <= idx_max; i++) {
val = vals[i];
+ if (!val)
+ continue;
printf(" %-10d : %-8d |", base + i * step, val);
print_stars(val, val_max, stars_max);
printf("|\n");
