Set 256 byte payload as the default in the Device Control Register to allow
the PCIe subsystem to enable 256 byte Max Payload Size when a capable link
partner is connected.

Link: https://lore.kernel.org/r/20220721142052.25971-13-vidyas@nvidia.comSigned-off-by: NVidya Sagar <vidyas@nvidia.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>