Use the port device name for the iov device for Chelsio T4/T5 cards.

Chelsio T4/T5 adapters are multifunction cards. The main driver uses
physical function 4 (PF4). However, VF devices for SR-IOV are only
supported on physical functions 0 through 3, where PF0 creates VFs tied
to port 0, etc. The t4iov/t5iov driver was previously added to
create VF devices for ports that are present on each adapter. This
change uses the recently added pci_iov_attach_name() function to
name the character device in /dev/iov after the associated port on
the card (e.g. /dev/iov/cxl0 is used to create VFs that share the
cxl0 port). With this in place, mark the t4iov/t5iov devices quiet
to prevent them from cluttering dmesg.

Reviewed by: rstone
Sponsored by: Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D7402