bnx2x: added support for working with one msix irq.

bnx2x: added support for working with one msix irq.

Until now, the bnx2x driver needed at least 2 available msix interrupt
vectors in order to use msix. This patch add the possibility of configuring
msix when only one interrupt vector is available.
Notice this patch contains lines with over 80 characters, as it keeps print
strings in a single line.

(cherry picked from commit 30a5de7723a8a4211be02e94236e9167a424fd07)
Signed-off-by: Dmitry Kravkov <dmitry@broadcom.com>
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>
Signed-off-by: Joe Jin <joe.jin@oracle.com>