ewrk3/tulip: Move the DEC - Tulip drivers

Move the DEC - Tulip driver into drivers/net/ethernet/dec/tulip/
and make the necessary Kconfig and Makefile changes.

The Digital Equioment (DEC) driver ewrk3 was moved into
drivers/net/ethernet/dec/ and the remaining drivers (Tulip)
were moved into drivers/net/ethernet/dec/tulip/

CC: Tobias Ringstrom <tori@unhappy.mine.nu>
CC: Grant Grundler <grundler@parisc-linux.org>
CC: David Davies <davies@maniac.ultranet.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Acked-by: Grant Grundler <grundler@parisc-linux.org>