efi_loader: add return to efibootmgr event group

When the image loaded by efibootmgr returns, efibootmgr
needs to clean the resources. Adding the event of returning
to efibootmgr is useful to simplify the implementation.

Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
diff --git a/include/efi_api.h b/include/efi_api.h
index c2d6964..0e92cb8 100644
--- a/include/efi_api.h
+++ b/include/efi_api.h
@@ -404,6 +404,9 @@
 #define EFI_EVENT_GROUP_RESET_SYSTEM \
 	EFI_GUID(0x62da6a56, 0x13fb, 0x485a, 0xa8, 0xda, \
 		 0xa3, 0xdd, 0x79, 0x12, 0xcb, 0x6b)
+#define EFI_EVENT_GROUP_RETURN_TO_EFIBOOTMGR \
+	EFI_GUID(0xb4a40fe6, 0x9149, 0x4f29, 0x94, 0x47, \
+		 0x49, 0x38, 0x7a, 0x7f, 0xab, 0x87)
 
 /* EFI Configuration Table and GUID definitions */
 #define NULL_GUID \