It's impossible to tell in general whether there's a vulnerability in a random number generator. It's a "computationally infeasible" problem, the best we can do is check for known deviations from randomness. If you know how it deviates, it's easy to check but beyond that there's no way to tell.
Unless the NIST tools are compromised as well, then yes, it's completely possible to verify how good hardware RNGs are. Also, few intel processors have built-in RNGs, at least not ones the Linux kernel can use. None of the machines we've bought in the last 5 years have them. When was the last major intel x86 processor to have one? P2/P3 based systems?
I always wondered why; now I think I know *exactly* why. Hardware RNGs increase crypto security; by removing them, the NSA can influence/corrupt OS-level pseudo-RNG routines.
I wonder how many of the software RNG projects like haveged are compromised...