greybus: fix manifest parsing problem with descriptor payload

The internal struct manifest_desc needs the data payload, rather
than the entire descriptor with header to be populated into the
data field. Also fix two places where the parser was trying to
extract the entire descriptor with header for the data payload
field.
Signed-off-by: Matt Porter <mporter@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

drivers/staging/greybus/manifest.c

@@ -113,7 +113,7 @@ static int identify_descriptor(struct greybus_descriptor *desc, size_t size)
 		return -ENOMEM;
 
 	descriptor->size = desc_size;
-	descriptor->data = desc;
+	descriptor->data = (u8 *)desc + sizeof(*desc_header);
 	descriptor->type = desc_header->type;
 	list_add_tail(&descriptor->links, &manifest_descs);
 
@@ -143,13 +143,11 @@ static char *gb_string_get(u8 string_id)
 		return NULL;
 
 	list_for_each_entry(descriptor, &manifest_descs, links) {
-		struct greybus_descriptor *desc;
 
 		if (descriptor->type != GREYBUS_TYPE_STRING)
 			continue;
 
-		desc = descriptor->data;
-		desc_string = &desc->string;
+		desc_string = descriptor->data;
 		if (desc_string->id == string_id) {
 			found = true;
 			break;
@@ -262,8 +260,7 @@ static u32 gb_manifest_parse_interfaces(struct gb_module *gmod)
 static bool gb_manifest_parse_module(struct gb_module *gmod,
 					struct manifest_desc *module_desc)
 {
-	struct greybus_descriptor *desc = module_desc->data;
-	struct greybus_descriptor_module *desc_module = &desc->module;
+	struct greybus_descriptor_module *desc_module = module_desc->data;
 
 	/* Handle the strings first--they can fail */
 	gmod->vendor_string = gb_string_get(desc_module->vendor_stringid);