IB/hfi1: Convert PCIBIOS_* errors to generic -E* errors

pcie_speeds() and restore_pci_variables() returns PCIBIOS_ error codes
from PCIe capability accessors.

PCIBIOS_ error codes have positive values. Passing on these values is
inconsistent with functions which return only a negative value on failure.

Before passing on the return value of PCIe capability accessors, call
pcibios_err_to_errno() to convert any positive PCIBIOS_ error codes to
negative generic error values.

Link: https://lore.kernel.org/r/20200615073225.24061-3-refactormyself@gmail.com


Suggested-by: Bjorn Helgaas <bjorn@helgaas.com>
Signed-off-by: Bolarinwa Olayemi Saheed <refactormyself@gmail.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>