eficonfig: CTRL+S to save the boot order

The change boot order menu in eficonfig can have at most INT_MAX lines
and it is troublesome to scroll down to the "Save" entry.

This commit assigns CTRL+S to save the boot order.

Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org>
Acked-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/cmd/eficonfig.c b/cmd/eficonfig.c
index f365a98..0a17b8c 100644
--- a/cmd/eficonfig.c
+++ b/cmd/eficonfig.c
@@ -28,7 +28,7 @@
 static const char *eficonfig_change_boot_order_desc =
 	"  Press UP/DOWN to move, +/- to change orde\n"
 	"  Press SPACE to activate or deactivate the entry\n"
-	"  Select [Save] to complete, ESC to quit";
+	"  CTRL+S to save, ESC to quit";
 
 static struct efi_simple_text_output_protocol *cout;
 static int avail_row;
@@ -1983,6 +1983,10 @@
 				eficonfig_menu_down(efi_menu);
 
 			return NULL;
+		case BKEY_SAVE:
+			/* force to select "Save" entry */
+			efi_menu->active = efi_menu->count - 2;
+			fallthrough;
 		case BKEY_SELECT:
 			/* "Save" */
 			if (efi_menu->active == efi_menu->count - 2) {
diff --git a/common/menu.c b/common/menu.c
index cdcdbb2..9451417 100644
--- a/common/menu.c
+++ b/common/menu.c
@@ -503,6 +503,9 @@
 	case CTL_CH('n'):
 		key = BKEY_DOWN;
 		break;
+	case CTL_CH('s'):
+		key = BKEY_SAVE;
+		break;
 	case '+':
 		key = BKEY_PLUS;
 		break;
diff --git a/include/menu.h b/include/menu.h
index 1e88141..64ce89b 100644
--- a/include/menu.h
+++ b/include/menu.h
@@ -53,6 +53,7 @@
 	BKEY_PLUS,
 	BKEY_MINUS,
 	BKEY_SPACE,
+	BKEY_SAVE,
 
 	BKEY_COUNT,
 };