ARM: OMAP4: Fix NULL pointer dereference crash.

After the patch series "[PATCH 00/14] OMAP PM fixes for .31-rc"
merge in 2.6.31-rc5, the kernel crashed during boot on OMAP4430.
This patch fixes it by adding UART4 support and related code.
Without this patch omap_serial_init() would produce " NULL pointer
dereference" and kernel crashes in the bootup on OMAP4430 platform.

Some more info on the merge issue can be found here.
More info- http://lkml.org/lkml/2009/8/20/192

Note: While merging this patch,"IO_ADDRESS" needs to be changed
to "OMAP2_IO_ADDRESS" if the Tony's below series is already merged in.
http://www.mail-archive.com/linux-omap@vger.kernel.org/msg15072.html

id = 3 instead of "PLAT8250_DEV_FOURPORT" as suggested by Kevin.
Signed-off-by: Syed Rafiuddin <rafiuddin.syed@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>

arch/arm/mach-omap2/board-4430sdp.c

@@ -39,7 +39,7 @@ static struct platform_device *sdp4430_devices[] __initdata = {
 };
 
 static struct omap_uart_config sdp4430_uart_config __initdata = {
-	.enabled_uarts	= (1 << 0) | (1 << 1) | (1 << 2),
+	.enabled_uarts	= (1 << 0) | (1 << 1) | (1 << 2) | (1 << 3),
 };
 
 static struct omap_lcd_config sdp4430_lcd_config __initdata = {

arch/arm/mach-omap2/serial.c

@@ -112,7 +112,21 @@ static struct plat_serial8250_port serial_platform_data2[] = {
 		.flags		= 0
 	}
 };
-
+#ifdef CONFIG_ARCH_OMAP4
+static struct plat_serial8250_port serial_platform_data3[] = {
+	{
+		.membase	= IO_ADDRESS(OMAP_UART4_BASE),
+		.mapbase	= OMAP_UART4_BASE,
+		.irq		= 70,
+		.flags		= UPF_BOOT_AUTOCONF,
+		.iotype		= UPIO_MEM,
+		.regshift	= 2,
+		.uartclk	= OMAP24XX_BASE_BAUD * 16,
+	}, {
+		.flags		= 0
+	}
+};
+#endif
 static inline unsigned int serial_read_reg(struct plat_serial8250_port *up,
 					   int offset)
 {
@@ -550,6 +564,17 @@ static struct omap_uart_state omap_uart[OMAP_MAX_NR_PORTS] = {
 			},
 		},
 	},
+#ifdef CONFIG_ARCH_OMAP4
+	{
+		.pdev = {
+			.name			= "serial8250",
+			.id			= 3,
+			.dev			= {
+				.platform_data	= serial_platform_data3,
+			},
+		},
+	},
+#endif
 };
 
 void __init omap_serial_init(void)