Fix test function derive_key_exercise()

mbedtls_test_psa_setup_key_derivation_wrap() returns 1 for success, 0
for error, so the test here was wrong.

This is just a hotfix in order to avoid a testing gap. Larger issues not
addressed here:

- I don't think we should just exit and mark the test as passed; if
we're not doing the actual testing this should be marked as SKIP.
- Returning 1 for success and 0 for failure is a violation of our
documented coding guidelines. We're also supposed to test with == 0 or
!= 0. Having consistent conventions is supposed to help avoid errors
like this.

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>

tests/suites/test_suite_psa_crypto.function

@@ -7946,7 +7946,7 @@ void derive_key_exercise( int alg_arg,
                                 &base_key ) );
 
     /* Derive a key. */
-    if ( mbedtls_test_psa_setup_key_derivation_wrap( &operation, base_key, alg,
+    if ( !mbedtls_test_psa_setup_key_derivation_wrap( &operation, base_key, alg,
                                                      input1->x, input1->len,
                                                      input2->x, input2->len,
                                                      capacity ) )