serial: samsung: Change barrier() to cpu_relax() in console output

The two functions to write out to the console (one used in normal
console mode and one in polling console mode) were slightly different.
One used a barrier() in its loop and the other a cpu_relax().  The
barrier() really doesn't do anything since we're using rd_regl() to
read the port anyway.  Switch it to cpu_relax() to make things
consistent.

No known bugs / issues are fixed by this change--it just makes things
more consistent.

Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/samsung.c

@@ -1466,7 +1466,7 @@ s3c24xx_serial_console_putchar(struct uart_port *port, int ch)
 	unsigned int ufcon = rd_regl(port, S3C2410_UFCON);
 
 	while (!s3c24xx_serial_console_txrdy(port, ufcon))
-		barrier();
+		cpu_relax();
 	wr_regb(port, S3C2410_UTXH, ch);
 }