serial: 8250: 8250_omap: Clear UART_HAS_RHR_IT_DIS bit

This fixes commit 439c718 ("serial: 8250: 8250_omap: Disable RX
interrupt after DMA enable") which unfortunately set the
UART_HAS_RHR_IT_DIS bit in the UART_OMAP_IER2 register and never
cleared it.

Cc: stable@vger.kernel.org
Fixes: 439c718 ("serial: 8250: 8250_omap: Disable RX interrupt after DMA enable")
Signed-off-by: Ronald Wahl <ronald.wahl@raritan.com>
Reviewed-by: Vignesh Raghavendra <vigneshr@ti.com>
Link: https://lore.kernel.org/r/20231031110909.11695-1-rwahl@gmx.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: tanstafel

drivers/tty/serial/8250/8250_omap.c

@@ -933,7 +933,7 @@ static void __dma_rx_do_complete(struct uart_8250_port *p)
 	if (priv->habit & UART_HAS_RHR_IT_DIS) {
 		reg = serial_in(p, UART_OMAP_IER2);
 		reg &= ~UART_OMAP_IER2_RHR_IT_DIS;
-		serial_out(p, UART_OMAP_IER2, UART_OMAP_IER2_RHR_IT_DIS);
+		serial_out(p, UART_OMAP_IER2, reg);
 	}
 
 	dmaengine_tx_status(rxchan, cookie, &state);
@@ -1079,7 +1079,7 @@ static int omap_8250_rx_dma(struct uart_8250_port *p)
 	if (priv->habit & UART_HAS_RHR_IT_DIS) {
 		reg = serial_in(p, UART_OMAP_IER2);
 		reg |= UART_OMAP_IER2_RHR_IT_DIS;
-		serial_out(p, UART_OMAP_IER2, UART_OMAP_IER2_RHR_IT_DIS);
+		serial_out(p, UART_OMAP_IER2, reg);
 	}
 
 	dma_async_issue_pending(dma->rxchan);