tty: s5pv210: Add delay loop on fifo reset function for UART

This patch addes delay loop on fifo reset function for UART.
On high speed freq, it needs delay function when fifo reset.
If not, system will hang by this uart reset problem when resuming
from suspend mode.

Signed-off-by: Jongpill Lee <boyko.lee@samsung.com>
Signed-off-by: Jaecheol Lee <jc.lee@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/tty/serial/s5pv210.c

@@ -18,6 +18,7 @@
 #include <linux/init.h>
 #include <linux/serial_core.h>
 #include <linux/serial.h>
+#include <linux/delay.h>
 
 #include <asm/irq.h>
 #include <mach/hardware.h>
@@ -83,6 +84,9 @@ static int s5pv210_serial_resetport(struct uart_port *port,
 	wr_regl(port, S3C2410_UFCON, cfg->ufcon | S3C2410_UFCON_RESETBOTH);
 	wr_regl(port, S3C2410_UFCON, cfg->ufcon);
 
+	/* It is need to delay When reset FIFO register */
+	udelay(1);
+
 	return 0;
 }