staging: rtl8723bs: Remove set but not used variable 'prwskeylen'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/staging/rtl8723bs/core/rtw_security.c: In function rtw_tkip_encrypt:
drivers/staging/rtl8723bs/core/rtw_security.c:660:6: warning: variable prwskeylen set but not used [-Wunused-but-set-variable]
drivers/staging/rtl8723bs/core/rtw_security.c: In function rtw_tkip_decrypt:
drivers/staging/rtl8723bs/core/rtw_security.c:768:6: warning: variable prwskeylen set but not used [-Wunused-but-set-variable]
drivers/staging/rtl8723bs/core/rtw_security.c: In function rtw_aes_encrypt:
drivers/staging/rtl8723bs/core/rtw_security.c:1528:6: warning: variable prwskeylen set but not used [-Wunused-but-set-variable]

It is not used since commit 554c0a3a ("staging:
Add rtl8723bs sdio wifi driver")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Link: https://lore.kernel.org/r/1570352999-45790-4-git-send-email-zhengbin13@huawei.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8723bs/core/rtw_security.c

@@ -656,7 +656,6 @@ u32 rtw_tkip_encrypt(struct adapter *padapter, u8 *pxmitframe)
 	u8   hw_hdr_offset = 0;
 	struct arc4context mycontext;
 	sint			curfragnum, length;
-	u32 prwskeylen;
 
 	u8 *pframe, *payload, *iv, *prwskey;
 	union pn48 dot11txpn;
@@ -703,8 +702,6 @@ u32 rtw_tkip_encrypt(struct adapter *padapter, u8 *pxmitframe)
 				/* prwskey =&stainfo->dot118021x_UncstKey.skey[0]; */
 				prwskey = pattrib->dot118021x_UncstKey.skey;
 
-			prwskeylen = 16;
-
 			for (curfragnum = 0; curfragnum < pattrib->nr_frags; curfragnum++) {
 				iv = pframe+pattrib->hdrlen;
 				payload = pframe+pattrib->iv_len+pattrib->hdrlen;
@@ -764,7 +761,6 @@ u32 rtw_tkip_decrypt(struct adapter *padapter, u8 *precvframe)
 	u8 crc[4];
 	struct arc4context mycontext;
 	sint			length;
-	u32 prwskeylen;
 
 	u8 *pframe, *payload, *iv, *prwskey;
 	union pn48 dot11txpn;
@@ -819,10 +815,8 @@ u32 rtw_tkip_decrypt(struct adapter *padapter, u8 *precvframe)
 				/* DBG_871X("rx bc/mc packets, to perform sw rtw_tkip_decrypt\n"); */
 				/* prwskey = psecuritypriv->dot118021XGrpKey[psecuritypriv->dot118021XGrpKeyid].skey; */
 				prwskey = psecuritypriv->dot118021XGrpKey[prxattrib->key_index].skey;
-				prwskeylen = 16;
 			} else {
 				prwskey = &stainfo->dot118021x_UncstKey.skey[0];
-				prwskeylen = 16;
 			}
 
 			iv = pframe+prxattrib->hdrlen;
@@ -1524,7 +1518,6 @@ u32 rtw_aes_encrypt(struct adapter *padapter, u8 *pxmitframe)
 
 	/* Intermediate Buffers */
 	sint	curfragnum, length;
-	u32 prwskeylen;
 	u8 *pframe, *prwskey;	/*  *payload,*iv */
 	u8   hw_hdr_offset = 0;
 	/* struct	sta_info 	*stainfo = NULL; */
@@ -1551,8 +1544,6 @@ u32 rtw_aes_encrypt(struct adapter *padapter, u8 *pxmitframe)
 			/* prwskey =&stainfo->dot118021x_UncstKey.skey[0]; */
 			prwskey = pattrib->dot118021x_UncstKey.skey;
 
-		prwskeylen = 16;
-
 		for (curfragnum = 0; curfragnum < pattrib->nr_frags; curfragnum++) {
 			if ((curfragnum+1) == pattrib->nr_frags) {	/* 4 the last fragment */
 				length = pattrib->last_txcmdsz-pattrib->hdrlen-pattrib->iv_len-pattrib->icv_len;