mx31ads: imoux pins should be passed in as unsigned int

To match the mxc_iomux_setup_multiple_pins() prototype.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

arch/arm/mach-mx3/mx31ads.c

@@ -102,7 +102,7 @@ static struct imxuart_platform_data uart_pdata = {
 	.flags = IMXUART_HAVE_RTSCTS,
 };
 
-static int uart_pins[] = {
+static unsigned int uart_pins[] = {
 	MX31_PIN_CTS1__CTS1,
 	MX31_PIN_RTS1__RTS1,
 	MX31_PIN_TXD1__TXD1,