w1: ds2490: use kmemdup rather than duplicating its implementation

Use kmemdup rather than duplicating its implementation.

Generated by: scripts/coccinelle/api/memdup.cocci
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Acked-by: NMaciej S. Szmigiero <mail@maciej.szmigiero.name>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/w1/masters/ds2490.c

@@ -909,11 +909,10 @@ static void ds9490r_write_block(void *data, const u8 *buf, int len)
 	if (len <= 0)
 		return;
 
-	tbuf = kmalloc(len, GFP_KERNEL);
+	tbuf = kmemdup(buf, len, GFP_KERNEL);
 	if (!tbuf)
 		return;
 
-	memcpy(tbuf, buf, len);
 	ds_write_block(dev, tbuf, len);
 
 	kfree(tbuf);