IB/hfi1: Unsuccessful PCIe caps tuning should not fail driver load

Failure to tune PCIe capabilities should not fail driver load. This can
cause the driver load to fail on systems with any of the following:
1. HFI's parent is not root. Example: HFI card is behind a PCIe bridge.
2. HFI's parent is not PCI Express capable.
In these situations, failure to tune PCIe capabilities should be logged
in the system message logs but not cause the driver load to fail.

This patch also ensures pcie capability word DevCtl is written only
after a successful read and the capability tuning process continues
even if read/write of the pcie capability word DevCtl fails.

Fixes: c53df62c ("IB/hfi1: Check return values from PCI config API calls")
Fixes: bf70a775 ("staging/rdma/hfi1: Enable WFR PCIe extended tags from the driver")
Reviewed-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Reviewed-by: Jakub Byczkowski <jakub.byczkowski@intel.com>
Signed-off-by: Harish Chegondi <harish.chegondi@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>