arm: exynos5: Migrate USB_BOOTING to Kconfig

This symbol is enabled for all exynos5 platforms, move to Kconfig and
select it.

Cc: Jaehoon Chung <jh80.chung@samsung.com>
Cc: Minkyu Kang <mk7.kang@samsung.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/arm/mach-exynos/Kconfig b/arch/arm/mach-exynos/Kconfig
index 29e35e4..383af83 100644
--- a/arch/arm/mach-exynos/Kconfig
+++ b/arch/arm/mach-exynos/Kconfig
@@ -4,6 +4,9 @@
 	def_bool y
 	depends on !TARGET_SMDKV310 && !TARGET_ARNDALE
 
+config USB_BOOTING
+	bool
+
 choice
 	prompt "EXYNOS architecture type select"
 	optional
@@ -24,6 +27,7 @@
 	select BOARD_EARLY_INIT_F
 	select CPU_V7A
 	select SHA_HW_ACCEL
+	select USB_BOOTING
 	imply CMD_HASH
 	imply CRC32_VERIFY
 	imply HASH_VERIFY