fconf: Clean Arm IO

Merge the previously introduced arm_fconf_io_storage into arm_io_storage. This
removes the duplicate io_policies and functions definition.

This patch:
- replace arm_io_storage.c with the content of arm_fconf_io_storage.c
- rename the USE_FCONF_BASED_IO option into ARM_IO_IN_DTB.
- use the ARM_IO_IN_DTB option to compile out io_policies moved in dtb.
- propagate DEFINES when parsing dts.
- use ARM_IO_IN_DTB to include or not uuid nodes in fw_config dtb.
- set the ARM_IO_IN_DTB to 0 by default for fvp. This ensure that the behavior
  of fvp stays the same as it was before the introduction of fconf.

Change-Id: Ia774a96d1d3a2bccad29f7ce2e2b4c21b26c080e
Signed-off-by: Louis Mayencourt <louis.mayencourt@arm.com>
diff --git a/lib/fconf/fconf.c b/lib/fconf/fconf.c
index 9ce4635..3007273 100644
--- a/lib/fconf/fconf.c
+++ b/lib/fconf/fconf.c
@@ -33,7 +33,7 @@
 	err = load_auth_image(TB_FW_CONFIG_ID, &arm_tb_fw_info);
 	if (err != 0) {
 		/* Return if FW_CONFIG is not loaded */
-		VERBOSE("Failed to load FW_CONFIG\n");
+		WARN("Failed to load FW_CONFIG\n");
 		return;
 	}