detachables: Select power off after language selection

Set current selection to power off after exiting the languages menu.
Previously, we were just defaulting to selecting the 0 index.  However,
this won't work anymore if we hide the "Enable Developer Mode" entry
in the recovery menu due to that entry being at the 0th index.

BUG=b:63078243, b:35585623
BRANCH=None
TEST=Boot into recovery when machine in normal mode.
     Select languages menu, make language selection and make sure
     that when return to recovery menu, power off item is selected.

Change-Id: I479c2270ca99197fd8c44386ab1ca4526ae7d64a
Signed-off-by: Shelley Chen <shchen@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/565527
Reviewed-by: Randall Spangler <rspangler@chromium.org>
diff --git a/firmware/lib/vboot_ui_menu.c b/firmware/lib/vboot_ui_menu.c
index deab020..29c561b 100644
--- a/firmware/lib/vboot_ui_menu.c
+++ b/firmware/lib/vboot_ui_menu.c
@@ -572,10 +572,29 @@
 			 * because need to do in different order.
 			 */
 			current_menu = prev_menu;
-			current_menu_idx = 0;
 			prev_menu = VB_MENU_LANGUAGES;
-			selected = 0;
-
+			/* default to power off index */
+			switch (current_menu) {
+			case VB_MENU_DEV_WARNING:
+				current_menu_idx = VB_WARN_POWER_OFF;
+				break;
+			case VB_MENU_DEV:
+				current_menu_idx = VB_DEV_POWER_OFF;
+				break;
+			case VB_MENU_TO_NORM:
+				current_menu_idx = VB_TO_NORM_POWER_OFF;
+				break;
+			case VB_MENU_RECOVERY:
+				current_menu_idx = VB_RECOVERY_POWER_OFF;
+				break;
+			case VB_MENU_TO_DEV:
+				current_menu_idx = VB_TO_DEV_POWER_OFF;
+				break;
+			default:
+				current_menu_idx = 0;
+				break;
+			}
+			selected = current_menu_idx;
 			break;
 		}
 	default: