The register to enable/disable PCI DMA IO has many variants, so define
and use a field to control it accordingly.
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20231026120049.9187-5-pkshih@realtek.com