Build: Add hardware key support to MCUBoot

Makes possible in MCUBoot to get the hash of ROTPK
from SoC.

Change-Id: I1a26a526c025b38dce49e91903d69bb9c5d619c0
Signed-off-by: Tamas Ban <tamas.ban@arm.com>
diff --git a/bl2/ext/mcuboot/MCUBootConfig.cmake b/bl2/ext/mcuboot/MCUBootConfig.cmake
index e7cc5c0..800e8fb 100644
--- a/bl2/ext/mcuboot/MCUBootConfig.cmake
+++ b/bl2/ext/mcuboot/MCUBootConfig.cmake
@@ -25,6 +25,8 @@
 	set_property(CACHE MCUBOOT_SIGNATURE_TYPE PROPERTY STRINGS "RSA-3072;RSA-2048")
 	validate_cache_value(MCUBOOT_SIGNATURE_TYPE)
 
+	set(MCUBOOT_HW_KEY Off CACHE BOOL "Configure to use HW key for image verification. Otherwise key is embedded in MCUBoot image.")
+
 	if ((${MCUBOOT_UPGRADE_STRATEGY} STREQUAL "NO_SWAP" OR
 		 ${MCUBOOT_UPGRADE_STRATEGY} STREQUAL "RAM_LOADING") AND
 		NOT (MCUBOOT_IMAGE_NUMBER EQUAL 1))
@@ -37,11 +39,13 @@
 
 	if (DEFINED MCUBOOT_IMAGE_NUMBER OR
 		DEFINED MCUBOOT_UPGRADE_STRATEGY OR
-		DEFINED MCUBOOT_SIGNATURE_TYPE)
+		DEFINED MCUBOOT_SIGNATURE_TYPE OR
+		DEFINED MCUBOOT_HW_KEY)
 		message(WARNING "Ignoring the values of MCUBOOT_* variables as BL2 option is set to False.")
 		set(MCUBOOT_IMAGE_NUMBER "")
 		set(MCUBOOT_UPGRADE_STRATEGY "")
 		set(MCUBOOT_SIGNATURE_TYPE "")
+		set(MCUBOOT_HW_KEY "")
 	endif()
 
 	if (DEFINED SECURITY_COUNTER OR