tty: serial: imx: remove dead code imx_dma_rxint

Since commit 4dec2f119e86 ("imx-serial: RX DMA startup latency")
the interrupt routine no longer will start rx dma.

imx_dma_rxint no longer needs to be called to try and start dma.
It won't start dma because dma_is_rxing is
already true meaning dma is already started.

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/imx.c

@@ -732,29 +732,6 @@ static void imx_disable_rx_int(struct imx_port *sport)
 }
 
 static void clear_rx_errors(struct imx_port *sport);
-static int start_rx_dma(struct imx_port *sport);
-/*
- * If the RXFIFO is filled with some data, and then we
- * arise a DMA operation to receive them.
- */
-static void imx_dma_rxint(struct imx_port *sport)
-{
-	unsigned long temp;
-	unsigned long flags;
-
-	spin_lock_irqsave(&sport->port.lock, flags);
-
-	temp = readl(sport->port.membase + USR2);
-	if ((temp & USR2_RDR) && !sport->dma_is_rxing) {
-
-		imx_disable_rx_int(sport);
-
-		/* tell the DMA to receive the data. */
-		start_rx_dma(sport);
-	}
-
-	spin_unlock_irqrestore(&sport->port.lock, flags);
-}
 
 /*
  * We have a modem side uart, so the meanings of RTS and CTS are inverted.
@@ -816,11 +793,8 @@ static irqreturn_t imx_int(int irq, void *dev_id)
 	sts = readl(sport->port.membase + USR1);
 	sts2 = readl(sport->port.membase + USR2);
 
-	if (sts & (USR1_RRDY | USR1_AGTIM)) {
-		if (sport->dma_is_enabled)
-			imx_dma_rxint(sport);
-		else
-			imx_rxint(irq, dev_id);
+	if (!sport->dma_is_enabled && (sts & (USR1_RRDY | USR1_AGTIM))) {
+		imx_rxint(irq, dev_id);
 		ret = IRQ_HANDLED;
 	}