efi_loader: use const efi_guid_t * for variable services

The runtime variable services never change GUIDs. So we should declare
the GUID parameters as constant.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/include/efi_api.h b/include/efi_api.h
index 4389dbe..83fd12b 100644
--- a/include/efi_api.h
+++ b/include/efi_api.h
@@ -221,13 +221,15 @@
 			struct efi_mem_desc *virtmap);
 	efi_status_t (*convert_pointer)(unsigned long dbg, void **address);
 	efi_status_t (EFIAPI *get_variable)(u16 *variable_name,
-					    efi_guid_t *vendor, u32 *attributes,
+					    const efi_guid_t *vendor,
+					    u32 *attributes,
 					    efi_uintn_t *data_size, void *data);
 	efi_status_t (EFIAPI *get_next_variable_name)(
 			efi_uintn_t *variable_name_size,
-			u16 *variable_name, efi_guid_t *vendor);
+			u16 *variable_name, const efi_guid_t *vendor);
 	efi_status_t (EFIAPI *set_variable)(u16 *variable_name,
-					    efi_guid_t *vendor, u32 attributes,
+					    const efi_guid_t *vendor,
+					    u32 attributes,
 					    efi_uintn_t data_size, void *data);
 	efi_status_t (EFIAPI *get_next_high_mono_count)(
 			uint32_t *high_count);
diff --git a/include/efi_loader.h b/include/efi_loader.h
index 6323686..5420c99 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -510,15 +510,15 @@
 				 struct efi_system_table *systab);
 #endif
 
-efi_status_t EFIAPI efi_get_variable(u16 *variable_name, efi_guid_t *vendor,
-				     u32 *attributes, efi_uintn_t *data_size,
-				     void *data);
+efi_status_t EFIAPI efi_get_variable(u16 *variable_name,
+				     const efi_guid_t *vendor, u32 *attributes,
+				     efi_uintn_t *data_size, void *data);
 efi_status_t EFIAPI efi_get_next_variable_name(efi_uintn_t *variable_name_size,
 					       u16 *variable_name,
-					       efi_guid_t *vendor);
-efi_status_t EFIAPI efi_set_variable(u16 *variable_name, efi_guid_t *vendor,
-				     u32 attributes, efi_uintn_t data_size,
-				     void *data);
+					       const efi_guid_t *vendor);
+efi_status_t EFIAPI efi_set_variable(u16 *variable_name,
+				     const efi_guid_t *vendor, u32 attributes,
+				     efi_uintn_t data_size, void *data);
 
 /*
  * See section 3.1.3 in the v2.7 UEFI spec for more details on