PCI: Drop "setting latency timer" messages

This message isn't useful any more, so drop it.

Reference: https://bugzilla.kernel.org/show_bug.cgi?id=60636
Reported-by: Oleksil Shevchuk <alxchk@gmail.com>
Reference: http://lkml.kernel.org/r/CALCETrWkr53ZjqdN3t7rTTfr=+ZKZXJoYsuBcwPf0kN_33GfAw@mail.gmail.com
Reported-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>