Currently, the driver has separate logic to determine device coherency
for DT vs ACPI.  This patch simplifies the code with a call to
device_dma_is_coherent().
Signed-off-by: NTom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: NSuravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>