bl2: add bl2_plat_handle_pre_image_load()

There are cases where we need to manipulate image information before
the load.  For example, for decompressing data, we cannot load the
compressed images to their final destination.  Instead, we need to
load them to the temporary buffer for the decompressor.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/plat/common/platform_helpers_default.c b/plat/common/platform_helpers_default.c
index 75c5199..597a585 100644
--- a/plat/common/platform_helpers_default.c
+++ b/plat/common/platform_helpers_default.c
@@ -13,6 +13,8 @@
 
 #pragma weak plat_error_handler
 #pragma weak bl2_plat_preload_setup
+#pragma weak bl2_plat_handle_pre_image_load
+#pragma weak bl2_plat_handle_post_image_load
 #pragma weak plat_try_next_boot_source
 
 void __dead2 plat_error_handler(int err)
@@ -25,6 +27,16 @@
 {
 }
 
+int bl2_plat_handle_pre_image_load(unsigned int image_id)
+{
+	return 0;
+}
+
+int bl2_plat_handle_post_image_load(unsigned int image_id)
+{
+	return 0;
+}
+
 int plat_try_next_boot_source(void)
 {
 	return 0;