drm/amdgpu: Fix consecutive DPC recovery failures.

Cache the PCI state on boot and before each case where we might
loose it.

v2: Add pci_restore_state while caching the PCI state to avoid
breaking PCI core logic for stuff like suspend/resume.

v3: Extract pci_restore_state from amdgpu_device_cache_pci_state
to avoid superflous restores during GPU resets and suspend/resumes.

v4: Style fixes.

Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/amd/amdgpu/nv.c b/drivers/gpu/drm/amd/amdgpu/nv.c
index 4d14023..0ec6603 100644
--- a/drivers/gpu/drm/amd/amdgpu/nv.c
+++ b/drivers/gpu/drm/amd/amdgpu/nv.c
@@ -311,7 +311,7 @@ static int nv_asic_mode1_reset(struct amdgpu_device *adev)
 	/* disable BM */
 	pci_clear_master(adev->pdev);
 
-	pci_save_state(adev->pdev);
+	amdgpu_device_cache_pci_state(adev->pdev);
 
 	if (amdgpu_dpm_is_mode1_reset_supported(adev)) {
 		dev_info(adev->dev, "GPU smu mode1 reset\n");
@@ -323,7 +323,7 @@ static int nv_asic_mode1_reset(struct amdgpu_device *adev)
 
 	if (ret)
 		dev_err(adev->dev, "GPU mode1 reset failed\n");
-	pci_restore_state(adev->pdev);
+	amdgpu_device_load_pci_state(adev->pdev);
 
 	/* wait for asic to come out of reset */
 	for (i = 0; i < adev->usec_timeout; i++) {