Fix typo in valgrind constant-time annotations.

This was causing valgrind to complain its internals were confused.

Change-Id: I1ba064b80666d62bd82bef052c66b927764ea078
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/36904
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/crypto/fipsmodule/rsa/rsa_impl.c b/crypto/fipsmodule/rsa/rsa_impl.c
index 903ba9a..ab2abe9 100644
--- a/crypto/fipsmodule/rsa/rsa_impl.c
+++ b/crypto/fipsmodule/rsa/rsa_impl.c
@@ -554,7 +554,7 @@
   if (!ret) {
     OPENSSL_PUT_ERROR(RSA, RSA_R_PADDING_CHECK_FAILED);
   } else {
-    CONSTTIME_DECLASSIFY(out, out_len);
+    CONSTTIME_DECLASSIFY(out, *out_len);
   }
 
 err: