ACPI: Adding DMA Attribute APIs for ACPI Device

Adding acpi_get_dma_attr() to query DMA attributes of ACPI devices.
It returns the enum dev_dma_attr, which communicates DMA information
more clearly. This API replaces the acpi_check_dma(), which will be
removed in subsequent patch.

This patch also provides a convenient function, acpi_dma_supported(),
to check DMA support of the specified ACPI device.

Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 496265b..292af3b 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -579,6 +579,16 @@
 	return false;
 }
 
+static inline bool acpi_dma_supported(struct acpi_device *adev)
+{
+	return false;
+}
+
+static inline enum dev_dma_attr acpi_get_dma_attr(struct acpi_device *adev)
+{
+	return DEV_DMA_NOT_SUPPORTED;
+}
+
 #define ACPI_PTR(_ptr)	(NULL)
 
 #endif	/* !CONFIG_ACPI */