PCI: pciehp: make check_link_active more helpful

A few changes:
  - remove the 'inline' and let the complier decide
  - return a bool to indicate whether the link was active
  - add a debug message to indicate link state when it beocmes active

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>