rng-tools: provide TRNG as a source of entropy to Edison

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>

meta-intel-edison-distro/recipes-core/images/edison-image-minimal.bb

@@ -78,6 +78,9 @@ IMAGE_INSTALL_append = " e2fsprogs-e2fsck e2fsprogs-mke2fs e2fsprogs-tune2fs e2f
 # Time related
 IMAGE_INSTALL_append = " tzdata"
 
+# linux 5.0.0 requires a source of entropy, use TRNG
+IMAGE_INSTALL_append = " rng-tools"
+
 IMAGE_INSTALL_append = " libgpiod"
 
 # Add monitoring tools