drm/radeon: Prefer pcie_capability_read_word()

[ Upstream commit 3d581b11e34a92350983e5d3ecf469b5c677e295 ]

Commit 8c0d3a02 ("PCI: Add accessors for PCI Express Capability")
added accessors for the PCI Express Capability so that drivers didn't
need to be aware of differences between v1 and v2 of the PCI
Express Capability.

Replace pci_read_config_word() and pci_write_config_word() calls with
pcie_capability_read_word() and pcie_capability_write_word().

Link: https://lore.kernel.org/r/20191118003513.10852-1-fred@fredlawl.com


Signed-off-by: Frederick Lawler <fred@fredlawl.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Stable-dep-of: 7189576e8a82 ("drm/radeon: Use RMW accessors for changing LNKCTL")
Signed-off-by: Sasha Levin <sashal@kernel.org>