[nrf noup] zephyr: Enforce HMAC-SHA512 for NRF54L with X25519

ECIES-X25519 key exchange on NRF54L will be using HMAC-SHA512
for MAC tagging encryption key.

Signed-off-by: Dominik Ermel <[email protected]>
(cherry picked from commit 8b2d04c)

Author: de-nordic

boot/zephyr/Kconfig

@@ -777,6 +777,7 @@ if BOOT_ENCRYPT_X25519 && BOOT_USE_PSA_CRYPTO
 
 choice BOOT_HMAC_SHA
 	prompt "SHA used for HMAC and HKDF in encryption key exchange"
+	default BOOT_HMAC_SHA512 if BOOT_ENCRYPT_X25519 && (SOC_NRF54L15_CPUAPP || SOC_NRF54LM20A_ENGA_CPUAPP)
 	default BOOT_HMAC_SHA256
 	help
 	  HMAC/HKDF sha algorithm may be selected to synchronize sha