via-*: Move the VIA drivers

Move the VIA drivers into drivers/net/ethernet/via/ and make the
necessary Kconfig and Makefile changes.

CC: Roger Luethi <rl@hellgate.ch>
CC: Francois Romieu <romieu@fr.zoreil.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>