rtc: abx80x: fix the RTC_VL_CLR clearing all status flags

[ Upstream commit 419719c ]

The RTC_VL_CLR ioctl intends to clear only the battery low flag (BLF),
however the current implementation writes 0 to the status register,
clearing all status bits.

Fix this by writing back the masked status value so that only BLF is
cleared, preserving other status flags.

Fixes: ffe1c5a ("rtc: abx80x: Implement RTC_VL_READ,CLR ioctls")
Signed-off-by: Antoni Pokusinski <apokusinski01@gmail.com>
Link: https://patch.msgid.link/20260415160610.127155-2-apokusinski01@gmail.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: panantoni01

drivers/rtc/rtc-abx80x.c

@@ -533,7 +533,8 @@ static int abx80x_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 
 		status &= ~ABX8XX_STATUS_BLF;
 
-		tmp = i2c_smbus_write_byte_data(client, ABX8XX_REG_STATUS, 0);
+		tmp = i2c_smbus_write_byte_data(client, ABX8XX_REG_STATUS,
+						status);
 		if (tmp < 0)
 			return tmp;