mx53evk: add boot_mode support

This allows a watchdog reset to start the ROM's
usb/serial downloader, or boot from an sdcard.

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
diff --git a/board/freescale/mx53evk/mx53evk.c b/board/freescale/mx53evk/mx53evk.c
index 8a6e31d..7f50938 100644
--- a/board/freescale/mx53evk/mx53evk.c
+++ b/board/freescale/mx53evk/mx53evk.c
@@ -28,6 +28,7 @@
 #include <asm/arch/crm_regs.h>
 #include <asm/arch/iomux.h>
 #include <asm/errno.h>
+#include <asm/imx-common/boot_mode.h>
 #include <netdev.h>
 #include <i2c.h>
 #include <mmc.h>
@@ -367,11 +368,23 @@
 	return 0;
 }
 
+#ifdef CONFIG_CMD_BMODE
+static const struct boot_mode board_boot_modes[] = {
+	/* 4 bit bus width */
+	{"mmc0",	MAKE_CFGVAL(0x40, 0x20, 0x00, 0x12)},
+	{"mmc1",	MAKE_CFGVAL(0x40, 0x20, 0x08, 0x12)},
+	{NULL,		0},
+};
+#endif
+
 int board_late_init(void)
 {
 	setup_i2c(1);
 	power_init();
 
+#ifdef CONFIG_CMD_BMODE
+	add_board_boot_modes(board_boot_modes);
+#endif
 	return 0;
 }