staging: rtl8712: remove multiple multiple assignments

Documentation/process/coding-style.rst says (in line 88)
"Don't put multiple assignments on a single line either."

This patch fixes the coding style issue reported by checkpatch.pl.
Signed-off-by: Alexander Vorwerk <alec@vc-celle.de>
Link: https://lore.kernel.org/r/20210501234501.5411-1-alec@vc-celle.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8712/rtl8712_recv.c

@@ -1039,8 +1039,9 @@ static void recvbuf2recvframe(struct _adapter *padapter, struct sk_buff *pskb)
 		skb_reserve(pkt_copy, 4 - ((addr_t)(pkt_copy->data) % 4));
 		skb_reserve(pkt_copy, shift_sz);
 		memcpy(pkt_copy->data, pbuf, tmp_len);
-		precvframe->u.hdr.rx_head = precvframe->u.hdr.rx_data =
-			precvframe->u.hdr.rx_tail = pkt_copy->data;
+		precvframe->u.hdr.rx_head = pkt_copy->data;
+		precvframe->u.hdr.rx_data = pkt_copy->data;
+		precvframe->u.hdr.rx_tail = pkt_copy->data;
 		precvframe->u.hdr.rx_end = pkt_copy->data + alloc_sz;
 
 		recvframe_put(precvframe, tmp_len);