a: use CONFIG_USB_BOOT_FIRST

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>

configs/a_defconfig

 CONFIG_ARM=y
 CONFIG_ARCH_MX6=y
 CONFIG_SYS_TEXT_BASE=0x17800000
+CONFIG_USB_BOOT_FIRST=y
 CONFIG_TARGET_A=y
 CONFIG_ENV_VARS_UBOOT_CONFIG=y
 CONFIG_SYS_EXTRA_OPTIONS="IMX_CONFIG=board/boundary/a/a_s512m.cfg,MX6S,DDR_MB=512,DEFCONFIG=\"a\""

include/configs/a.h

@@ -18,9 +18,6 @@
 #define CONFIG_SYS_FSL_USDHC_NUM	1
 #define CONFIG_USB_MAX_CONTROLLER_COUNT 1
 #define BD_I2C_MASK	2
-#define BOOT_TARGET_DEVICES(func) \
-	DISTRO_BOOT_DEV_USB(func) \
-	DISTRO_BOOT_DEV_MMC(func)
 #define BD_USB_START 	"setexpr otgstat *0x020c9030 \\\\& 0x08000000;" \
 				"if itest.l ${otgstat} -eq 0 ; then " \
 					"usb start;" \