fix(ff-a): partitions boot order

Partitions have the "boot-order" field in their partitions manifest,
that is meant to be used to dictate the order in which SPs are
initialized.
Partitions were being booted from higher to lower of their respective
"boot-order" value. The correct behavior should be from lower to
higher.

Change-Id: I040070f76166d914690b05d568aac9cfce2af713
Signed-off-by: J-Alves <joao.alves@arm.com>
diff --git a/inc/hf/manifest.h b/inc/hf/manifest.h
index 97364b7..c045432 100644
--- a/inc/hf/manifest.h
+++ b/inc/hf/manifest.h
@@ -30,7 +30,8 @@
 /** Mask for getting read/write/execute permission */
 #define MM_PERM_MASK 0x7
 
-#define DEFAULT_BOOT_ORDER 0x0
+/* Highest possible value for the boot-order field. */
+#define DEFAULT_BOOT_ORDER 0xFFFF
 
 enum run_time_el {
 	EL1 = 0,