wandboard: Staticize usdhc1_pads

Fix the following sparse warning:

wandboard.c:58:22: warning: symbol 'usdhc1_pads' was not declared. Should it be static?

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>

board/wandboard/wandboard.c

@@ -55,7 +55,7 @@ static iomux_v3_cfg_t const uart1_pads[] = {
 	MX6_PAD_CSI0_DAT11__UART1_RX_DATA | MUX_PAD_CTRL(UART_PAD_CTRL),
 };
 
-iomux_v3_cfg_t const usdhc1_pads[] = {
+static iomux_v3_cfg_t const usdhc1_pads[] = {
 	MX6_PAD_SD1_CLK__SD1_CLK   | MUX_PAD_CTRL(USDHC_PAD_CTRL),
 	MX6_PAD_SD1_CMD__SD1_CMD   | MUX_PAD_CTRL(USDHC_PAD_CTRL),
 	MX6_PAD_SD1_DAT0__SD1_DATA0 | MUX_PAD_CTRL(USDHC_PAD_CTRL),