psa: Initialize crypto in tests that need to

Don't unconditionally enable PSA Crypto for all tests. Only enable it in
tests that require it. This allows crypto tests to check that
psa_crypto_init() fails when it is supposed to fail, since we want to
perform some action in a test, and then call psa_crypto_init() and check
the result without it having been called previously.
diff --git a/tests/suites/test_suite_cipher.function b/tests/suites/test_suite_cipher.function
index f973399..a7d3a6e 100644
--- a/tests/suites/test_suite_cipher.function
+++ b/tests/suites/test_suite_cipher.function
@@ -962,6 +962,8 @@
 #else
     if( use_psa == 1 )
     {
+        TEST_ASSERT( psa_crypto_init() == 0 );
+
         /* PSA requires that the tag immediately follows the ciphertext. */
         tmp_cipher = mbedtls_calloc( 1, cipher->len + tag->len );
         TEST_ASSERT( tmp_cipher != NULL );
@@ -1104,6 +1106,7 @@
 #else
     if( use_psa == 1 )
     {
+        TEST_ASSERT( psa_crypto_init() == 0 );
         TEST_ASSERT( 0 == mbedtls_cipher_setup_psa( &ctx,
                               mbedtls_cipher_info_from_type( cipher_id ), 0 ) );
     }