drm/amdgpu: enable swiotlb for gmc 10.0 (V2)

Enable swiotlb for gmc 10.0.
v2: include drm_cache.h to use the function ‘drm_need_swiotlb’
Signed-off-by: Aaron Liu <aaron.liu@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c

@@ -22,6 +22,9 @@
  */
 #include <linux/firmware.h>
 #include <linux/pci.h>
+
+#include <drm/drm_cache.h>
+
 #include "amdgpu.h"
 #include "amdgpu_atomfirmware.h"
 #include "gmc_v10_0.h"
@@ -980,6 +983,8 @@ static int gmc_v10_0_sw_init(void *handle)
 		return r;
 	}
 
+	adev->need_swiotlb = drm_need_swiotlb(44);
+
 	r = gmc_v10_0_mc_init(adev);
 	if (r)
 		return r;