SUNRPC: Fixup gss_status tracepoint error output

The GSS routine errors are values, not flags.

Fixes: 0c77668d ("SUNRPC: Introduce trace points in rpc_auth_gss.ko")
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>