cfg80211: regulatory: Fix inconsistent format argument

Fix follow warning:
[net/wireless/reg.c:3619]: (warning) %d in format string (no. 2)
requires 'int' but the argument type is 'unsigned int'.
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Ye Bin <yebin10@huawei.com>
Link: https://lore.kernel.org/r/20201009070215.63695-1-yebin10@huawei.comSigned-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/reg.c

@@ -3616,7 +3616,7 @@ static void print_rd_rules(const struct ieee80211_regdomain *rd)
 		power_rule = &reg_rule->power_rule;
 
 		if (reg_rule->flags & NL80211_RRF_AUTO_BW)
-			snprintf(bw, sizeof(bw), "%d KHz, %d KHz AUTO",
+			snprintf(bw, sizeof(bw), "%d KHz, %u KHz AUTO",
 				 freq_range->max_bandwidth_khz,
 				 reg_get_max_bandwidth(rd, reg_rule));
 		else