IB/qib: Use pcie_set_mps() and pcie_get_mps() to simplify code
IB/qib: Use pcie_set_mps() and pcie_get_mps() to simplify code

Refactor qib_tune_pcie_caps().  Use pcie_get_mps(), pcie_set_mps(),
pcie_get_readrq(), and pcie_set_readrq() to simplify the code.  The PCI
core caches the "PCIe Max Payload Size Supported" in pci_dev->pcie_mpss,
so use that instead of pcie_capability_read_word().  Remove the unused
val2fld() and fld2val().

Signed-off-by: Yijing Wang <ac442ed3e729ed4f09d087e9c319e1c47c72d6f1@huawei.com>
Signed-off-by: Bjorn Helgaas <f10ec01be0c6b54271af5c550cd257810bdf3268@google.com>
Acked-by: Mike Marciniszyn <8b6671d72f65e2bb5dd5241f258fc1c5c815d085@intel.com>
KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs