When the ethaddr changes in the env, the hardware should also be updated
so that MAC filtering will work properly without resetting U-Boot.

Also remove the manual calls to set the hwaddr that was included in a
few drivers as a result of the framework not doing it.

Reported-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
Tested-by: Michal Simek <michal.simek@xilinx.com>