efi_loader: export a couple of protocol related functions

This is a preparatory patch.
Those functions will be used in an implementation of UEFI firmware
management protocol as part of my capsule update patch.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
diff --git a/include/efi_loader.h b/include/efi_loader.h
index 8e34379..37c3f15 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -457,6 +457,20 @@
 /* Install multiple protocol interfaces */
 efi_status_t EFIAPI efi_install_multiple_protocol_interfaces
 				(efi_handle_t *handle, ...);
+/* Get handles that support a given protocol */
+efi_status_t EFIAPI efi_locate_handle_buffer(
+			enum efi_locate_search_type search_type,
+			const efi_guid_t *protocol, void *search_key,
+			efi_uintn_t *no_handles, efi_handle_t **buffer);
+/* Close an previously opened protocol interface */
+efi_status_t EFIAPI efi_close_protocol(efi_handle_t handle,
+				       const efi_guid_t *protocol,
+				       efi_handle_t agent_handle,
+				       efi_handle_t controller_handle);
+/* Open a protocol interface */
+efi_status_t EFIAPI efi_handle_protocol(efi_handle_t handle,
+					const efi_guid_t *protocol,
+					void **protocol_interface);
 /* Call this to create an event */
 efi_status_t efi_create_event(uint32_t type, efi_uintn_t notify_tpl,
 			      void (EFIAPI *notify_function) (