[PATCH] bcm43xx: Workaround init_board vs IRQ race.

The proper fix for this is to move IRQ enabling to the end of
init_board. But this is nontrivial and needs to be done with care.
Stay with this cheap workaround for now.

Signed-off-by: Michael Buesch <mbuesch@freenet.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>