serial: xilinx_uartps: cache xmit in cdns_uart_handle_tx()

Cache port->state->xmit into a local variable (xmit) in
cdns_uart_handle_tx(). This reduces length of some lines there
significantly. I.e. makes the code more readable.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220421101708.5640-4-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/xilinx_uartps.c

@@ -313,29 +313,26 @@ static void cdns_uart_handle_rx(void *dev_id, unsigned int isrstatus)
 static void cdns_uart_handle_tx(void *dev_id)
 {
 	struct uart_port *port = (struct uart_port *)dev_id;
+	struct circ_buf *xmit = &port->state->xmit;
 	unsigned int numbytes;
 
-	if (uart_circ_empty(&port->state->xmit)) {
+	if (uart_circ_empty(xmit)) {
 		writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_IDR);
 		return;
 	}
 
 	numbytes = port->fifosize;
-	while (numbytes && !uart_circ_empty(&port->state->xmit) &&
-	       !(readl(port->membase + CDNS_UART_SR) &
-					CDNS_UART_SR_TXFULL)) {
+	while (numbytes && !uart_circ_empty(xmit) &&
+	       !(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXFULL)) {
 
-		writel(port->state->xmit.buf[port->state->xmit.tail],
-				port->membase + CDNS_UART_FIFO);
+		writel(xmit->buf[xmit->tail], port->membase + CDNS_UART_FIFO);
 
 		port->icount.tx++;
-		port->state->xmit.tail = (port->state->xmit.tail + 1) &
-				(UART_XMIT_SIZE - 1);
-
+		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
 		numbytes--;
 	}
 
-	if (uart_circ_chars_pending(&port->state->xmit) < WAKEUP_CHARS)
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 		uart_write_wakeup(port);
 }