lib_*/board.c: do not initialize bi_enet*addr in global data

lib_*/board.c: do not initialize bi_enet*addr in global data

Since everyone is using the environment for mac address storage, there is
no point in seeding the global data.

The arches that are converted here:
	i386
	m68k
	microblaze
	mips
	nios
	nios2
	sh
	sparc

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
CC: Ben Warren <biggerbadderben@gmail.com>
CC: Daniel Hellstrom <daniel@gaisler.com>
CC: Michal Simek <monstr@seznam.cz>
CC: Shinya Kuribayashi <skuribay@ruby.dti.ne.jp>
CC: Scott McNutt <smcnutt@psyent.com>
CC: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>