NFC: microread: Remove redundant assignment to variable err

In the case MICROREAD_CB_TYPE_READER_ALL clang reports a dead code
warning. The error code assigned to variable err is already passed
to async_cb(). The assignment is redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: NNigel Christian <nigel.l.christian@gmail.com>
Reviewed-by: NKrzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/nfc/microread/microread.c

@@ -364,7 +364,6 @@ static void microread_im_transceive_cb(void *context, struct sk_buff *skb,
 	case MICROREAD_CB_TYPE_READER_ALL:
 		if (err == 0) {
 			if (skb->len == 0) {
-				err = -EPROTO;
 				kfree_skb(skb);
 				info->async_cb(info->async_cb_context, NULL,
 					       -EPROTO);