drivers/net/usb: Use kmemdup

Use kmemdup when some other buffer is immediately copied into the
allocated region.

A simplified version of the semantic patch that makes this change is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
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);
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/usb/mcs7830.c b/drivers/net/usb/mcs7830.c
index 834d8cd..a6281e3 100644
--- a/drivers/net/usb/mcs7830.c
+++ b/drivers/net/usb/mcs7830.c
@@ -142,12 +142,10 @@
 	int ret;
 	void *buffer;
 
-	buffer = kmalloc(size, GFP_NOIO);
+	buffer = kmemdup(data, size, GFP_NOIO);
 	if (buffer == NULL)
 		return -ENOMEM;
 
-	memcpy(buffer, data, size);
-
 	ret = usb_control_msg(xdev, usb_sndctrlpipe(xdev, 0), MCS7830_WR_BREQ,
 			      MCS7830_WR_BMREQ, 0x0000, index, buffer,
 			      size, MCS7830_CTRL_TIMEOUT);