net: Remove all calls to net_random_ethaddr()

Remove the calls to net_random_ethaddr() that some boards and some
drivers are calling. This is now implemented inside of net/eth.c

Enable the feature for all boards that previously enabled it.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
Acked-By: Michael Walle <michael@walle.cc> (for the lsxl board part)

Series-changes: 2
-Fixed bfin build errors