wifi: rtl8xxxu: fix authentication timeout due to incorrect RCR value

When using rtl8192cu with rtl8xxxu driver to connect wifi, there is a
probability of failure, which shows "authentication with ... timed out".
Through debugging, it was found that the RCR register has been inexplicably
modified to an incorrect value, resulting in the nic not being able to
receive authenticated frames.

To fix this problem, add regrcr in rtl8xxxu_priv struct, and store
the RCR value every time the register is written, and use it the next
time the register need to be modified.
Signed-off-by: Yun Lu <luyun@kylinos.cn>
Link: https://lore.kernel.org/all/20230427020512.1221062-1-luyun_611@163.comSigned-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230512012055.2990472-1-luyun_611@163.com

drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.h

@@ -1803,6 +1803,7 @@ struct rtl8xxxu_priv {
 	u32 rege9c;
 	u32 regeb4;
 	u32 regebc;
+	u32 regrcr;
 	int next_mbox;
 	int nr_out_eps;
 

drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c

@@ -4171,6 +4171,7 @@ static int rtl8xxxu_init_device(struct ieee80211_hw *hw)
 		RCR_ACCEPT_MGMT_FRAME | RCR_HTC_LOC_CTRL |
 		RCR_APPEND_PHYSTAT | RCR_APPEND_ICV | RCR_APPEND_MIC;
 	rtl8xxxu_write32(priv, REG_RCR, val32);
+	priv->regrcr = val32;
 
 	if (fops->init_reg_rxfltmap) {
 		/* Accept all data frames */
@@ -6501,7 +6502,7 @@ static void rtl8xxxu_configure_filter(struct ieee80211_hw *hw,
 				      unsigned int *total_flags, u64 multicast)
 {
 	struct rtl8xxxu_priv *priv = hw->priv;
-	u32 rcr = rtl8xxxu_read32(priv, REG_RCR);
+	u32 rcr = priv->regrcr;
 
 	dev_dbg(&priv->udev->dev, "%s: changed_flags %08x, total_flags %08x\n",
 		__func__, changed_flags, *total_flags);
@@ -6547,6 +6548,7 @@ static void rtl8xxxu_configure_filter(struct ieee80211_hw *hw,
 	 */
 
 	rtl8xxxu_write32(priv, REG_RCR, rcr);
+	priv->regrcr = rcr;
 
 	*total_flags &= (FIF_ALLMULTI | FIF_FCSFAIL | FIF_BCN_PRBRESP_PROMISC |
 			 FIF_CONTROL | FIF_OTHER_BSS | FIF_PSPOLL |