A variable is unused in some configurations

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/tests/src/drivers/key_management.c b/tests/src/drivers/key_management.c
index c79069b..00d2b45 100644
--- a/tests/src/drivers/key_management.c
+++ b/tests/src/drivers/key_management.c
@@ -273,6 +273,7 @@
         return( PSA_ERROR_INVALID_ARGUMENT );
 
     psa_key_type_t keytype = psa_get_key_type( attributes );
+    (void) keytype;
 
 #if defined(MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_KEY_PAIR) || \
     defined(MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_PUBLIC_KEY)