Commit 6cea369b89 updated the TinyUSB
submodule to a version based on nrfx v2.0.0. This commit updates the nrf
port to work with the latest TinyUSB and nrfx v2.0.0.
The "random" module no longer uses the hardware RNG (the extmod version of
this module has a pseudo-random number generator), so the config option
MICROPY_PY_RANDOM_HW_RNG is no longer meaningful. This commit replaces it
with MICROPY_HW_ENABLE_RNG, which controls whether the hardware RNG is
included in the build.