IB/hfi1: Replace custom hfi1 macros with PCIe macros

IB/hfi1 contains custom macros for PCIe link configuration. Remove the
custom macros in favor of the PCIe link macros. No functional change
intended.

Signed-off-by: Frederick Lawler <fred@fredlawl.com>
[bhelgaas: use "GT" instead of "GB"]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Michael J. Ruhl <michael.j.ruhl@intel.com>