Revert "sysbuild: Allow selecting SHA512 for HMAC/HKDF in MCUboot"

Removing Kconfig for HMAC-SHA512 as currently it can be replaced
with logic in CMake files and Kconfigs, so exposing direct control
over it is not needed; specifically that the HMAC-SHA512 is now
only enabled on NRF54L series with ECIES-X25519 key exchange,
other platforms are left with originally selected HMAC-SHA256.

This reverts commit 293252a.

Signed-off-by: Dominik Ermel <[email protected]>
(cherry picked from commit 91d93d0)

Author: de-nordic

sysbuild/CMakeLists.txt

@@ -267,18 +267,11 @@ function(${SYSBUILD_CURRENT_MODULE_NAME}_pre_cmake)
           set_config_bool(mcuboot CONFIG_PSA_USE_CRACEN_MAC_DRIVER y)
           set_config_bool(mcuboot CONFIG_PSA_USE_CRACEN_KEY_AGREEMENT_DRIVER y)
           set_config_bool(mcuboot CONFIG_PSA_USE_CRACEN_KEY_DERIVATION_DRIVER y)
-
-          if(SB_CONFIG_NRF_MCUBOOT_HMAC_SHA512)
-            set_config_bool(mcuboot CONFIG_BOOT_HMAC_SHA512 y)
-          else()
-            set_config_bool(mcuboot CONFIG_BOOT_HMAC_SHA512 n)
-          endif()
         else()
           set_config_bool(mcuboot CONFIG_PSA_USE_CRACEN_CIPHER_DRIVER n)
           set_config_bool(mcuboot CONFIG_PSA_USE_CRACEN_MAC_DRIVER n)
           set_config_bool(mcuboot CONFIG_PSA_USE_CRACEN_KEY_AGREEMENT_DRIVER n)
           set_config_bool(mcuboot CONFIG_PSA_USE_CRACEN_KEY_DERIVATION_DRIVER n)
-          set_config_bool(mcuboot CONFIG_BOOT_HMAC_SHA512 n)
         endif()
 
         if(SB_CONFIG_MCUBOOT_SIGNATURE_USING_KMU)

sysbuild/Kconfig.mcuboot

@@ -198,15 +198,6 @@ config MCUBOOT_GENERATE_DEFAULT_KMU_KEYFILE
 	help
 	  If enabled, the build system will generate keyfile.json file in the build directory.
 
-config NRF_MCUBOOT_HMAC_SHA512
-	bool "Use SHA256 for HMAC"
-	depends on BOOT_ENCRYPTION && SOC_SERIES_NRF54LX && BOOT_SIGNATURE_TYPE_ED25519
-	help
-	  Default is to use SHA256 for HMAC/HKDF ECIES-X25519 key exchange is used.
-	  This means that both SHA256 and SHA512 support has to be compiled in.
-	  Enabling this option switches to SHA512 for HMAC/HKDF slightly reducing
-	  MCUboot code size.
-
 endif
 
 config MCUBOOT_USE_ALL_AVAILABLE_RAM