libc: Fix all includes in codebase

The codebase was using non-standard headers. It is needed to replace
them by the correct ones so that we can use the new libc headers.

Change-Id: I530f71d9510cb036e69fe79823c8230afe890b9d
Acked-by: Sumit Garg <sumit.garg@linaro.org>
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
diff --git a/plat/rpi3/rpi3_private.h b/plat/rpi3/rpi3_private.h
index 91b7add..368d09b 100644
--- a/plat/rpi3/rpi3_private.h
+++ b/plat/rpi3/rpi3_private.h
@@ -7,7 +7,7 @@
 #ifndef __RPI3_PRIVATE_H__
 #define __RPI3_PRIVATE_H__
 
-#include <sys/types.h>
+#include <stdint.h>
 
 /*******************************************************************************
  * Function and variable prototypes