samsung: misc: add env default option to lcd menu

This change allows reset device environment to default without using u-boot
console, which is useful for system developers.

Signed-off-by: Inha Song <ideal.song@samsung.com>
Acked-by: Przemyslaw Marczak <p.marczak@samsung.com>
Cc: Minkyu Kang <mk7.kang@samsung.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>

include/samsung/misc.h

@@ -16,6 +16,7 @@ enum {
 	BOOT_MODE_UMS,
 	BOOT_MODE_DFU,
 	BOOT_MODE_GPT,
+	BOOT_MODE_ENV,
 	BOOT_MODE_EXIT,
 };