bna: Move the Brocade driver

Moves the Brocade driver into drivers/net/ethernet/brocade/ and make
the necessary Kconfig and Makefile changes.

CC: Rasesh Mody <rmody@brocade.com>
CC: Debashis Dutt <ddutt@brocade.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>