feat(partition): add interface to init gpt

Current interface 'partition_init' accepts parameter image_id
and returns no value. But the entire partition driver is build
only to parse and handle GPT partitions, so add new interface
gpt_partition_init which would return failure to platform code
if it fails to parse the image.

Change-Id: Iaf574d2ad01a15d0723c1475290c31dc4a078835
Signed-off-by: Govindraj Raja <govindraj.raja@arm.com>

drivers/partition/partition.c

@@ -460,5 +460,19 @@ const partition_entry_list_t *get_partition_entry_list(void)
  */
 void partition_init(unsigned int image_id)
 {
-	load_partition_table(image_id);
+	int ret;
+
+	ret = load_partition_table(image_id);
+	if (ret != 0) {
+		ERROR("Failed to parse partition with image id = %u\n",
+		      image_id);
+	}
+}
+
+/*
+ * Load a GPT based image.
+ */
+int gpt_partition_init(void)
+{
+	return load_partition_table(GPT_IMAGE_ID);
 }

include/drivers/partition/partition.h

@@ -50,5 +50,6 @@ const partition_entry_t *get_partition_entry_by_type(const uuid_t *type_guid);
 const partition_entry_t *get_partition_entry_by_uuid(const uuid_t *part_uuid);
 const partition_entry_list_t *get_partition_entry_list(void);
 void partition_init(unsigned int image_id);
+int gpt_partition_init(void);
 
 #endif /* PARTITION_H */