Fix mistyped endif comment

Correct the endif comment to match the condition used in the ifdef.

Signed-off-by: David Brown <david.brown@linaro.org>
diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index 7f201f6..18f98c0 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -3915,7 +3915,7 @@
     }
     if( ret != 0 )
         goto exit;
-#endif /* MBEDTLS_PSA_BUILTIN_ALG_CBC_NO_PADDING || MBEDTLS_PADDING_PKCS7 */
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_CBC_NO_PADDING || MBEDTLS_PSA_BUILTIN_ALG_CBC_PKCS7 */
 
     operation->block_size = ( PSA_ALG_IS_STREAM_CIPHER( alg ) ? 1 :
                               PSA_BLOCK_CIPHER_BLOCK_LENGTH( slot->attr.type ) );