Make use of user/system includes more consistent

Make codebase consistent in its use of #include "" syntax for
user includes and #include <> syntax for system includes.

Fixes ARM-software/tf-issues#65

Change-Id: If2f7c4885173b1fd05ac2cde5f1c8a07000c7a33
diff --git a/plat/fvp/plat_io_storage.c b/plat/fvp/plat_io_storage.c
index 3c34f15..d44a71d 100644
--- a/plat/fvp/plat_io_storage.c
+++ b/plat/fvp/plat_io_storage.c
@@ -30,14 +30,14 @@
 
 #include <assert.h>
 #include <string.h>
-#include "platform.h"
-#include "io_storage.h"
-#include "io_driver.h"
-#include "io_semihosting.h"
-#include "semihosting.h"	/* For FOPEN_MODE_... */
-#include "io_fip.h"
-#include "io_memmap.h"
-#include "debug.h"
+#include <platform.h>
+#include <io_storage.h>
+#include <io_driver.h>
+#include <io_semihosting.h>
+#include <semihosting.h>	/* For FOPEN_MODE_... */
+#include <io_fip.h>
+#include <io_memmap.h>
+#include <debug.h>
 
 /* IO devices */
 static struct io_plat_data io_data;