Staging: wilc1000: cfg80211: Use kmemdup instead of kmalloc and memcpy

Replace calls to kmalloc followed by a memcpy with a direct call to
kmemdup.

The Coccinelle semantic patch used to make this change is as follows:
@@
expression from,to,size,flag;
statement S;
@@

-  to = \(kmalloc\|kzalloc\)(size,flag);
+  to = kmemdup(from,size,flag);
   if (to==NULL || ...) S
-  memcpy(to, from, size);
Signed-off-by: Shreeya Patel <shreeya.patel23498@gmail.com>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Link: https://lore.kernel.org/r/20200313112451.25610-1-shreeya.patel23498@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/wilc1000/cfg80211.c

@@ -1142,14 +1142,13 @@ static int mgmt_tx(struct wiphy *wiphy,
 		goto out;
 	}
 
-	mgmt_tx->buff = kmalloc(len, GFP_KERNEL);
+	mgmt_tx->buff = kmemdup(buf, len, GFP_KERNEL);
 	if (!mgmt_tx->buff) {
 		ret = -ENOMEM;
 		kfree(mgmt_tx);
 		goto out;
 	}
 
-	memcpy(mgmt_tx->buff, buf, len);
 	mgmt_tx->size = len;
 
 	if (ieee80211_is_probe_resp(mgmt->frame_control)) {