riscv: Add NVMe, USB and HID support to GENERIC

The SiFive FU740 has both NVMe and USB so we need both to ensure we can
mount root, and HID is a dependency of USB.

Reviewed by: kp
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D31036

(cherry picked from commit 6e162bd2f298b58a418a17d49f5671a9a113fc4e)