Clarify TLS 1.2 dependencies with and without PSA crypto

Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
diff --git a/library/check_crypto_config.h b/library/check_crypto_config.h
index d7ad16a..3924a68 100644
--- a/library/check_crypto_config.h
+++ b/library/check_crypto_config.h
@@ -88,4 +88,9 @@
 #error "PSA_WANT_KEY_TYPE_ECC_KEY_PAIR defined, but not all prerequisites"
 #endif
 
+#if defined(MBEDTLS_SSL_PROTO_TLS1_2) && defined(MBEDTLS_USE_PSA_CRYPTO) &&\
+    !(defined(PSA_WANT_ALG_SHA_1) || defined(PSA_WANT_ALG_SHA_256) || defined(PSA_WANT_ALG_SHA_512) )
+#error "MBEDTLS_SSL_PROTO_TLS1_2 defined, but not all prerequisites"
+#endif
+
 #endif /* MBEDTLS_CHECK_CRYPTO_CONFIG_H */