drm/amdgpu: resize VRAM BAR for CPU access on gfx10

Try to resize BAR0 to let CPU access all of VRAM on Navi. Syncs
code with previous gfx generations from commit d6895ad3
("drm/amdgpu: resize VRAM BAR for CPU access v6").
Signed-off-by: Alan Swanson <reiver@improbability.net>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -686,17 +686,23 @@ static void gmc_v10_0_vram_gtt_location(struct amdgpu_device *adev,
  */
 static int gmc_v10_0_mc_init(struct amdgpu_device *adev)
 {
-	/* Could aper size report 0 ? */
-	adev->gmc.aper_base = pci_resource_start(adev->pdev, 0);
-	adev->gmc.aper_size = pci_resource_len(adev->pdev, 0);
+	int r;
 
 	/* size in MB on si */
 	adev->gmc.mc_vram_size =
 		adev->nbio.funcs->get_memsize(adev) * 1024ULL * 1024ULL;
 	adev->gmc.real_vram_size = adev->gmc.mc_vram_size;
-	adev->gmc.visible_vram_size = adev->gmc.aper_size;
+
+	if (!(adev->flags & AMD_IS_APU)) {
+		r = amdgpu_device_resize_fb_bar(adev);
+		if (r)
+			return r;
+	}
+	adev->gmc.aper_base = pci_resource_start(adev->pdev, 0);
+	adev->gmc.aper_size = pci_resource_len(adev->pdev, 0);
 
 	/* In case the PCI BAR is larger than the actual amount of vram */
+	adev->gmc.visible_vram_size = adev->gmc.aper_size;
 	if (adev->gmc.visible_vram_size > adev->gmc.real_vram_size)
 		adev->gmc.visible_vram_size = adev->gmc.real_vram_size;