i825xx: Move the Intel 82586/82593/82596 based drivers

Move the drivers that use the i82586/i82593/i82596 chipsets into
drivers/net/ethernet/i825xx/ and make the necessary Kconfig and
Makefile changes.  There were 4 3Com drivers which were initially
moved into 3com/, which now reside in i825xx since they all used
the i82586 chip.

CC: Philip Blundell <philb@gnu.org>
CC: Russell King <linux@arm.linux.org.uk>
CC: <aris@cathedrallabs.org>
CC: Donald Becker <becker@scyld.com>
CC: Chris Beauregard <cpbeaure@undergrad.math.uwaterloo.ca>
CC: Richard Procter <rnp@paradise.net.nz>
CC: Andries Brouwer <aeb@cwi.nl>
CC: "M.Hipp" <hippm@informatik.uni-tuebingen.de>
CC: Richard Hirst <richard@sleepie.demon.co.uk>
CC: Sam Creasey <sammy@oh.verio.com>
CC: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>