Actually, it gives you as much entropy as you need, just increase the iterations. That guy's output is shockingly consistent, so to be conservative maybe we say 0.2 bits of entropy per iteration. So just do 1000 iterations. That's still only going to take a few milliseconds even on embedded hardware.

EDIT: I reviewed his code, and he's not hashing between calls to check the clock; the hash call itself causes the CPU to heat up in arbitrary ways which changes the timing between hashes and introduces more entropy; removing that call basically entirely defeats the idea behind the technique, these results are fully invalid.