For all PCI functions on the netxen_nic adapter, interrupt
mode (INTx or MSI) configuration is dependent on what has
been configured by the PCI function zero in the shared
interrupt register, as these adapters do not support mixed
mode interrupts among the functions of a given adapter.

Logic for setting MSI/MSI-x interrupt mode in the shared interrupt
register based on PCI function id zero check is not appropriate for
all family of netxen adapters, as for some of the netxen family
adapters PCI function zero is not really meant to be probed/loaded
in the host but rather just act as a management function on the device,
which caused all the other PCI functions on the adapter to always use
legacy interrupt (INTx) mode instead of choosing MSI/MSI-x interrupt mode.

This patch replaces that check with port number so that for all
type of adapters driver attempts for MSI/MSI-x interrupt modes.

Fixes: b37eb210 ("netxen_nic: Avoid mixed mode interrupts")
Signed-off-by: Manish Chopra <manishc@marvell.com>
Signed-off-by: Igor Russkikh <irusskikh@marvell.com>
Link: https://lore.kernel.org/r/20210107101520.6735-1-manishc@marvell.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>