Add StarFive JH7110 true random number generator driver

[jsihv_gmx.com]

Summary

TRNG driver for JH7110. A simple implementation which follows the algorithm used in OpenBSD (should this be mentioned on the code?). It has been tested that it calls random_harvest_queue() once in a second and passes data that looks random. Haven't seen any LFSR_LOCKUP happening.

[cem]

FYI, it's best practice to generate diffs with full context (-U999999 or whatever).