PCI/LINK: Deduplicate bandwidth reports for multi-function devices
If a multi-function device's bandwidth is already limited when it is
enumerated, a message is logged only for function 0. By contrast, when
downtraining occurs after enumeration, a message is logged for all
functions. That's because the former uses pcie_report_downtraining(),
whereas the latter uses __pcie_print_link_status() (which doesn't filter
functions != 0). I am seeing this happen on a MacBookPro9,1 with a GPU
(function 0) and an integrated HDA controller (function 1).
Avoid this incongruence by calling pcie_report_downtraining() in both
cases.