staging: r8188eu: fix led register settings

Using an InterTech DMG-02 dongle, the led remains on when the system goes
into standby mode. After wakeup, it's no longer possible to control the
led.

It turned out that the register settings to enable or disable the led were
not correct. They worked for some dongles like the Edimax V2 but not for
others like the InterTech DMG-02.

This patch fixes the register settings. Bit 3 in the led_cfg2 register
controls the led status, bit 5 must always be set to be able to control
the led, bit 6 has no influence on the led. Setting the mac_pinmux_cfg
register is not necessary.

These settings were tested with Edimax V2 and InterTech DMG-02.

Cc: stable@vger.kernel.org
Fixes: 8cd574e6 ("staging: r8188eu: introduce new hal dir for RTL8188eu driver")
Suggested-by: Michael Straube <straube.linux@gmail.com>
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Tested-by: Michael Straube <straube.linux@gmail.com> # InterTech DMG-02,
Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com> # Edimax N150
Link: https://lore.kernel.org/r/20221015151115.232095-2-martin@kaiser.cxSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/r8188eu/core/rtw_led.c

@@ -31,40 +31,19 @@ static void ResetLedStatus(struct led_priv *pLed)
 
 static void SwLedOn(struct adapter *padapter, struct led_priv *pLed)
 {
-	u8	LedCfg;
-	int res;
-
 	if (padapter->bDriverStopped)
 		return;
 
-	res = rtw_read8(padapter, REG_LEDCFG2, &LedCfg);
-	if (res)
-		return;
-
-	rtw_write8(padapter, REG_LEDCFG2, (LedCfg & 0xf0) | BIT(5) | BIT(6)); /*  SW control led0 on. */
+	rtw_write8(padapter, REG_LEDCFG2, BIT(5)); /*  SW control led0 on. */
 	pLed->bLedOn = true;
 }
 
 static void SwLedOff(struct adapter *padapter, struct led_priv *pLed)
 {
-	u8	LedCfg;
-	int res;
-
 	if (padapter->bDriverStopped)
 		goto exit;
 
-	res = rtw_read8(padapter, REG_LEDCFG2, &LedCfg);/* 0x4E */
-	if (res)
-		goto exit;
-
-	LedCfg &= 0x90; /*  Set to software control. */
-	rtw_write8(padapter, REG_LEDCFG2, (LedCfg | BIT(3)));
-	res = rtw_read8(padapter, REG_MAC_PINMUX_CFG, &LedCfg);
-	if (res)
-		goto exit;
-
-	LedCfg &= 0xFE;
-	rtw_write8(padapter, REG_MAC_PINMUX_CFG, LedCfg);
+	rtw_write8(padapter, REG_LEDCFG2, BIT(5) | BIT(3));
 exit:
 	pLed->bLedOn = false;
 }