It's apparently not very random. I just grabbed a sample by running this on the device:

dd if=/dev/hwrng of=dump

In visually examining the hex, I noticed a heck of a lot of 16's. To see if I was hallucinating, I ran this on the file:

for x in {0..9}; do od ./dump | grep -c ${x}6; done
11926
11238
7535
7351
7562
7352
6880
7419
0
0

Doesn't look like a very even distribution to me. Not a single 86 or 96 appeared in the sample.

I also noticed this bug report on it:

https://dev.laptop.org/ticket/8089