staging: rtl8723bs: Use % 4096 instead of & 0xfff

The sequence number is constrained to a range of [0, 4095], which
is a total of 4096 values. The bitmask operation using `& 0xfff` is
used to perform this wrap-around. While this is functionally correct,
it obscures the intended semantic of a 4096-based wrap.

Using a modulo operation `% 4096u` makes the wrap-around logic
explicit and easier to understand. It clearly signals that the
sequence number cycles through a range of 4096 values.
It also makes the code robust against potential changes of the 4096
upper limit, especially when it becomes a non power-of-2 value while
the AND(&) works solely for power-of-2 values.

The use of `% 4096u` also guarantees that the modulo operation is
performed with unsigned arithmetic, preventing potential issues with
the signed types.

Found by Coccinelle.

Suggested-by: Andy Shevchenko <[e-mail]>
Suggested-by: David Laight <[e-mail]>
Signed-off-by: Abraham Samuel Adekunle <[e-mail]>
Reviewed-by: Andy Shevchenko <[e-mail]>
Link: https://lore.kernel.org/r/e8d515539[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/rtl8723bs/core/rtw_mlme_ext.c

···
 			/* if ((psta = rtw_get_stainfo(pstapriv, pmlmeinfo->network.mac_address)) != NULL) */
 			psta = rtw_get_stainfo(pstapriv, raddr);
 			if (psta) {
-				start_seq = (psta->sta_xmitpriv.txseq_tid[status & 0x07]&0xfff) + 1;
+				start_seq = (psta->sta_xmitpriv.txseq_tid[status & 0x07] % 4096u) + 1;
 
 				psta->BA_starting_seqctrl[status & 0x07] = start_seq;
 

drivers/staging/rtl8723bs/core/rtw_recv.c

···
 	struct dvobj_priv *psdpriv = padapter->dvobj;
 	struct debug_priv *pdbgpriv = &psdpriv->drv_dbg;
 	u8 wsize = preorder_ctrl->wsize_b;
-	u16 wend = (preorder_ctrl->indicate_seq + wsize - 1) & 0xFFF;/*  4096; */
+	u16 wend = (preorder_ctrl->indicate_seq + wsize - 1) % 4096u;
 
 	/*  Rx Reorder initialize condition. */
 	if (preorder_ctrl->indicate_seq == 0xFFFF)
···
 	/*  2. Incoming SeqNum is larger than the WinEnd => Window shift N */
 	/*  */
 	if (SN_EQUAL(seq_num, preorder_ctrl->indicate_seq)) {
-		preorder_ctrl->indicate_seq = (preorder_ctrl->indicate_seq + 1) & 0xFFF;
+		preorder_ctrl->indicate_seq = (preorder_ctrl->indicate_seq + 1) % 4096u;
 
 	} else if (SN_LESS(wend, seq_num)) {
 		/*  boundary situation, when seq_num cross 0xFFF */
···
 			list_del_init(&(prframe->u.hdr.list));
 
 			if (SN_EQUAL(preorder_ctrl->indicate_seq, pattrib->seq_num))
-				preorder_ctrl->indicate_seq = (preorder_ctrl->indicate_seq + 1) & 0xFFF;
+				preorder_ctrl->indicate_seq = (preorder_ctrl->indicate_seq + 1) % 4096u;
 
 			/* Set this as a lock to make sure that only one thread is indicating packet. */
 			/* pTS->RxIndicateState = RXTS_INDICATE_PROCESSING; */

drivers/staging/rtl8723bs/core/rtw_xmit.c

···
 
 			if (psta) {
 				psta->sta_xmitpriv.txseq_tid[pattrib->priority]++;
-				psta->sta_xmitpriv.txseq_tid[pattrib->priority] &= 0xFFF;
+				psta->sta_xmitpriv.txseq_tid[pattrib->priority] %= 4096u;
 				pattrib->seqnum = psta->sta_xmitpriv.txseq_tid[pattrib->priority];
 
 				SetSeqNum(hdr, pattrib->seqnum);
···
 						pattrib->ampdu_en = false;/* AGG BK */
 					} else if (SN_EQUAL(pattrib->seqnum, tx_seq)) {
 						psta->BA_starting_seqctrl[pattrib->priority & 0x0f] =
-							(tx_seq + 1) & 0xfff;
+							(tx_seq + 1) % 4096u;
 
 						pattrib->ampdu_en = true;/* AGG EN */
 					} else {
 						psta->BA_starting_seqctrl[pattrib->priority & 0x0f] =
-							(pattrib->seqnum + 1) & 0xfff;
+							(pattrib->seqnum + 1) % 4096u;
 
 						pattrib->ampdu_en = true;/* AGG EN */
 					}