hippi: Move the HIPPI driver

Move the HIPPI driver into drivers/net/hippi/ and make the
necessary Kconfig and Makefile changes.

CC: Jes Sorensen <jes@wildopensource.com>
CC: Jes Sorensen <jes@trained-monkey.org>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>