bnxt_en: Simplify and improve unsupported SFP+ module reporting.

The current code is more complicated than necessary and can only report
unsupported SFP+ module if it is plugged in after the device is up.

Rename bnxt_port_module_event() to bnxt_get_port_module_status().  We
already have the current module_status in the link_info structure, so
just check that and report any unsupported SFP+ module status.  Delete
the unnecessary last_port_module_event.  Call this function at the
end of bnxt_open to report unsupported module already plugged in.

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