FWU: Add Generic Firmware Update framework support in BL1

Firmware update(a.k.a FWU) feature is part of the TBB architecture.
BL1 is responsible for carrying out the FWU process if platform
specific code detects that it is needed.

This patch adds support for FWU feature support in BL1 which is
included by enabling `TRUSTED_BOARD_BOOT` compile time flag.

This patch adds bl1_fwu.c which contains all the core operations
of FWU, which are; SMC handler, image copy, authentication, execution
and resumption. It also adds bl1.h introducing #defines for all
BL1 SMCs.

Following platform porting functions are introduced:

int bl1_plat_mem_check(uintptr_t mem_base, unsigned int mem_size,
unsigned int flags);
	This function can be used to add platform specific memory checks
	for the provided base/size for the given security state.
	The weak definition will invoke `assert()` and return -ENOMEM.

__dead2 void bl1_plat_fwu_done(void *cookie, void *reserved);
	This function can be used to initiate platform specific procedure
	to mark completion of the FWU process.
	The weak definition waits forever calling `wfi()`.

plat_bl1_common.c contains weak definitions for above functions.

FWU process starts when platform detects it and return the image_id
other than BL2_IMAGE_ID by using `bl1_plat_get_next_image_id()` in
`bl1_main()`.

NOTE: User MUST provide platform specific real definition for
bl1_plat_mem_check() in order to use it for Firmware update.

Change-Id: Ice189a0885d9722d9e1dd03f76cac1aceb0e25ed
diff --git a/bl1/bl1_private.h b/bl1/bl1_private.h
index 7d796f1..283bbb9 100644
--- a/bl1/bl1_private.h
+++ b/bl1/bl1_private.h
@@ -31,6 +31,8 @@
 #ifndef __BL1_PRIVATE_H__
 #define __BL1_PRIVATE_H__
 
+#include <types.h>
+
 /*******************************************************************************
  * Declarations of linker defined symbols which will tell us where BL1 lives
  * in Trusted RAM
@@ -47,4 +49,13 @@
 void bl1_arch_next_el_setup(void);
 
 void bl1_prepare_next_image(unsigned int image_id);
+
+register_t bl1_fwu_smc_handler(unsigned int smc_fid,
+		register_t x1,
+		register_t x2,
+		register_t x3,
+		register_t x4,
+		void *cookie,
+		void *handle,
+		unsigned int flags);
 #endif /* __BL1_PRIVATE_H__ */