drm/amdgpu: Remove accidentally added small unused hunk.

Commit 8f66090b ("drm/amdgpu: Remove references to struct drm_device.pdev")
accidentally adds an initialization of adev, which isn't used anywhere. This
caused a compiler warning on the unused variable, remove it.

Fixes: 8f66090b ("drm/amdgpu: Remove references to struct drm_device.pdev")
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Christian König <christian.koenig@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>

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

@@ -926,7 +926,6 @@ amdgpu_display_user_framebuffer_create(struct drm_device *dev,
 				       struct drm_file *file_priv,
 				       const struct drm_mode_fb_cmd2 *mode_cmd)
 {
-	struct amdgpu_device *adev = drm_to_adev(dev);
 	struct drm_gem_object *obj;
 	struct amdgpu_framebuffer *amdgpu_fb;
 	int ret;