boot/zephyr: Kconfig for hooks enabling

Added global property which allows to enable hooks
implementations.

Signed-off-by: Andrzej Puzdrowski <andrzej.puzdrowski@nordicsemi.no>
diff --git a/boot/zephyr/Kconfig b/boot/zephyr/Kconfig
index 4371589..f612b6d 100644
--- a/boot/zephyr/Kconfig
+++ b/boot/zephyr/Kconfig
@@ -642,6 +642,24 @@
 	  Enables implementation of MCUBOOT_WATCHDOG_FEED() macro which is
 	  used to feed watchdog while doing time consuming operations.
 
+config BOOT_IMAGE_ACCESS_HOOKS
+	bool "Enable hooks for overriding MCUboot's native routines"
+	help
+	  Allow to provide procedures for override or extend native
+	  MCUboot's routines required for access the image data and the image
+	  update.
+
+config BOOT_IMAGE_ACCESS_HOOKS_FILE
+	string "Hooks implementation file path"
+	depends on BOOT_IMAGE_ACCESS_HOOKS
+	help
+	  Path to the file which implements hooks.
+	  You can use either absolute or relative path.
+	  In case relative path is used, the build system assumes that it starts
+	  from the directory where the MCUBoot KConfig configuration file is
+	  located. If the key file is not there, the build system uses relative
+	  path that starts from the zephyr port cmake directory (boot/zephyr/).
+
 endmenu
 
 config MCUBOOT_DEVICE_SETTINGS