random: init and deinit live entropy sources

The functions intended to initialize and uninitialize
live entropy sources aren't being called.
Their role is to initialize and destroy a static global
mutex, respectively. Therefore, I would say that the lack
of calls hasn't prevented any CSPRNG functionality from
working as desired.

FreeBSD relies on SYS_INIT and SYSUNINIT to get those
functions called, respectively.
For OSv, let's simply remove their static modifiers such
that they will be properly called from the outside.

Reviewed-by: Nadav Har'El <nyh@cloudius-systems.com>
Signed-off-by: Raphael S. Carvalho <raphaelsc@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>