Newer versions of ssh require sufficient entropy prior to opening a connection.
But linux 4.20 and later does not gather entropy by default from the disk.
Other sources (mouse/keyboard/graphics/sound) on Edison are not present so
gathering entropy is slow. Use TRNG (true random number generator in the
processor to speed this up.

Signed-off-by: Ferry Toth <ftoth@exalondelft.nl>