usb: Fastboot function config for better consistency with other functions

USB download gadget functions such as thor and dfu have a separate config option
for the USB gadget part of the code, independent from the command part.
This switches the fastboot USB gadget to the same scheme, for better
consistency.

Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
Tested-by: Lukasz Majewski <l.majewski@samsung.com>

Test HW: Odroid_XU3 (Exynos5422), trats (Exynos4210)
diff --git a/include/configs/omap3_beagle.h b/include/configs/omap3_beagle.h
index 8ebb5bd..59c780e 100644
--- a/include/configs/omap3_beagle.h
+++ b/include/configs/omap3_beagle.h
@@ -72,6 +72,7 @@
 #define CONFIG_G_DNL_VENDOR_NUM		0x0451
 #define CONFIG_G_DNL_PRODUCT_NUM	0xd022
 #define CONFIG_G_DNL_MANUFACTURER	"TI"
+#define CONFIG_USB_FUNCTION_FASTBOOT
 #define CONFIG_CMD_FASTBOOT
 #define CONFIG_ANDROID_BOOT_IMAGE
 #define CONFIG_USB_FASTBOOT_BUF_ADDR	CONFIG_SYS_LOAD_ADDR