Remove several warnings reported with W=1

Improved support for W=1 compilation flag by solving missing-prototypes
and old-style-definition warnings.

The libraries are compiling with warnings (which turn into errors with
the Werror flag).

Outside of libraries, some warnings cannot be fixed without heavy
structural changes.

Change-Id: I1668cf99123ac4195c2a6a1d48945f7a64c67f16
Signed-off-by: Ambroise Vincent <ambroise.vincent@arm.com>
diff --git a/plat/arm/board/fvp/fvp_private.h b/plat/arm/board/fvp/fvp_private.h
index 3d96537..5067d3a 100644
--- a/plat/arm/board/fvp/fvp_private.h
+++ b/plat/arm/board/fvp/fvp_private.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014-2018, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2014-2019, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -20,5 +20,4 @@
 void fvp_interconnect_disable(void);
 void tsp_early_platform_setup(void);
 
-
 #endif /* FVP_PRIVATE_H */