wifi: cfg80211: Use kmemdup_array instead of kmemdup for multiple allocation

Let the kememdup_array() take care about multiplication and possible
overflows.

Signed-off-by: Yu Jiaoliang <[e-mail]>
Reviewed-by: Christophe JAILLET <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Johannes Berg <[e-mail]>

net/wireless/util.c

···
 		if (params->num_different_channels > c->num_different_channels)
 			continue;
 
-		limits = kmemdup(c->limits, sizeof(limits[0]) * c->n_limits,
-				 GFP_KERNEL);
+		limits = kmemdup_array(c->limits, c->n_limits, sizeof(*limits),
+				       GFP_KERNEL);
 		if (!limits)
 			return -ENOMEM;