fconf: Handle error from fconf_load_config

Updated 'fconf_load_config' function to return
the error.
Error from 'fconf_load_config" gets handled
by BL1 in subsequent patches.

Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
Change-Id: I4360f4df850e355b5762bb2d9666eb285101bc68
diff --git a/include/lib/fconf/fconf.h b/include/lib/fconf/fconf.h
index 7020f86..917e053 100644
--- a/include/lib/fconf/fconf.h
+++ b/include/lib/fconf/fconf.h
@@ -44,7 +44,7 @@
 };
 
 /* This function supports to load tb_fw_config and fw_config dtb */
-void fconf_load_config(unsigned int image_id);
+int fconf_load_config(unsigned int image_id);
 
 /* Top level populate function
  *