Boot: Use the same flash_map module as upstream MCUBoot

Add new sysflash.h and flash_map_extended.h files as they are needed to
build TF-M with the original MCUBoot. Some of the macro definitions and
function declarations from flash_map.h were moved into these
new headers.

Change-Id: I9b5ddeba9528c82c7ccfc59fbba5c661f0ad1084
Signed-off-by: David Vincze <david.vincze@arm.com>
diff --git a/bl2/ext/mcuboot/bootutil/src/loader.c b/bl2/ext/mcuboot/bootutil/src/loader.c
index 5acf6bc..e604677 100644
--- a/bl2/ext/mcuboot/bootutil/src/loader.c
+++ b/bl2/ext/mcuboot/bootutil/src/loader.c
@@ -21,7 +21,7 @@
  * Original code taken from mcuboot project at:
  * https://github.com/JuulLabs-OSS/mcuboot
  * Git SHA of the original version: ac55554059147fff718015be9f4bd3108123f50a
- * Modifications are Copyright (c) 2018-2019 Arm Limited.
+ * Modifications are Copyright (c) 2018-2020 Arm Limited.
  */
 
 /**
@@ -35,7 +35,9 @@
 #include <inttypes.h>
 #include <stdlib.h>
 #include <string.h>
+#include "sysflash/sysflash.h"
 #include "flash_map/flash_map.h"
+#include "flash_map_backend/flash_map_backend.h"
 #include "bootutil/bootutil.h"
 #include "bootutil/image.h"
 #include "bootutil_priv.h"