drm/amdgpu/display: include slab.h in dcn21_resource.c

It's apparently needed in some configurations.

Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Alex Deucher 2019-09-23 15:56:25 -05:00
commit d1249aae81