bnx2x: previous driver unload revised

The flow in which the bnx2x driver starts after a previous driver
has been terminated in an 'unclean' manner has several bugs and
FW risks, which makes it possible for the driver to fail after
boot-from-SAN or kdump.
This patch contains a revised flow which performs a safer
initialization, solving the possible crash scenarios.
Notice this patch contains lines with over 80 characters, as it
keeps print-strings in a single line.

Signed-off-by: Yuval Mintz <yuvalmin@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>