[PATCH] drm/amd/display: fix unused variable warning

[Arnd Bergmann]

From: Arnd Bergmann <arnd at arndb.de>

After all users of the 'dm' warnings got hidden in an #ifdef,
the compiler started warning about it being unused:

drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:5380:33: error: unused variable 'dm' [-Werror,-Wunused-variable]

Add another such #ifdef.

Fixes: 98ab5f3513f9 ("drm/amd/display: Fix deadlock during gpu reset v3")
Signed-off-by: Arnd Bergmann <arnd at arndb.de>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index a90dc4d31c32..37bf2dd87e1e 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -5377,7 +5377,9 @@ static inline int dm_set_vblank(struct drm_crtc *crtc, bool enable)
 	struct amdgpu_crtc *acrtc = to_amdgpu_crtc(crtc);
 	struct amdgpu_device *adev = drm_to_adev(crtc->dev);
 	struct dm_crtc_state *acrtc_state = to_dm_crtc_state(crtc->state);
+#if defined(CONFIG_DRM_AMD_DC_DCN)
 	struct amdgpu_display_manager *dm = &adev->dm;
+#endif
 	int rc = 0;
 
 	if (enable) {
-- 
2.29.2