bnx2: Fix problem of using wrong IRQ handler.

The MSI-X handler was chosen before the call to pci_enable_msix().
If MSI-X was not available, the wrong MSI-X handler would be used in
INTA mode.  This would cause a screaming interrupt problem because
INTA would not be cleared by the MSI-X handler.

Fixed by assigning MSI-X handler after pci_enable_msix() returns
successfully.  Also update version to 1.9.3.

Thomas Chenault <thomas_chenault@dell.com> helped us find this problem.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>