Simplify compile-time PSA/non-PSA ECDH(E) code in ssl_write_client_key_exchange()

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
diff --git a/library/ssl_tls12_client.c b/library/ssl_tls12_client.c
index 7471cd0..56aef89 100644
--- a/library/ssl_tls12_client.c
+++ b/library/ssl_tls12_client.c
@@ -2805,12 +2805,12 @@
     defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) ||                   \
     defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) ||                      \
     defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
-#if defined(MBEDTLS_USE_PSA_CRYPTO)
     if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_RSA ||
         ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA ||
         ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDH_RSA ||
         ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA )
     {
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
         psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
         psa_status_t destruction_status = PSA_ERROR_CORRUPTION_DETECTED;
         psa_key_attributes_t key_attributes;
@@ -2881,14 +2881,7 @@
 
         if( status != PSA_SUCCESS || destruction_status != PSA_SUCCESS )
             return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
-    }
-    else
 #else
-    if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_RSA ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDH_RSA ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA )
-    {
         /*
          * ECDH key exchange -- send client public value
          */
@@ -2948,9 +2941,9 @@
 
         MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
                                 MBEDTLS_DEBUG_ECDH_Z );
+#endif /* MBEDTLS_USE_PSA_CRYPTO */
     }
     else
-#endif /* MBEDTLS_USE_PSA_CRYPTO */
 #endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED ||
           MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED ||
           MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED ||