Fix small error in a comment

Use '||' instead of 'or' for consistency.

Signed-off-by: David Brown <david.brown@linaro.org>
diff --git a/include/mbedtls/config_psa.h b/include/mbedtls/config_psa.h
index 60ed72c..39069aa 100644
--- a/include/mbedtls/config_psa.h
+++ b/include/mbedtls/config_psa.h
@@ -277,7 +277,7 @@
 #if defined(PSA_WANT_ALG_CBC_PKCS7)
 #define MBEDTLS_CIPHER_PADDING_PKCS7
 #endif /* PSA_WANT_ALG_CBC_PKCS7 */
-#endif /* PSA_WANT_ALG_CBC_NO_PADDING or PSA_WANT_ALG_CBC_PKCS7 */
+#endif /* PSA_WANT_ALG_CBC_NO_PADDING || PSA_WANT_ALG_CBC_PKCS7 */
 
 #else /* MBEDTLS_PSA_CRYPTO_CONFIG */