drm/amdgpu: Fix warnings

Fix below warning due to incompatible types in conditional operator

../pm/swsmu/smu13/smu_v13_0_6_ppt.c:315:17: sparse: sparse: incompatible
types in conditional expression (different base types):
Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Luben Tuikov <luben.tuikov@amd.com>
Reviewed-by: Guchun Chen <guchun.chen@amd.com>
Link: https://lore.kernel.org/oe-kbuild-all/202303082135.NjdX1Bij-lkp@intel.com/Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu.h

@@ -1221,7 +1221,7 @@ int emu_soc_asic_init(struct amdgpu_device *adev);
 	((adev)->asic_funcs->flush_hdp ? (adev)->asic_funcs->flush_hdp((adev), (r)) : (adev)->hdp.funcs->flush_hdp((adev), (r)))
 #define amdgpu_asic_invalidate_hdp(adev, r) \
 	((adev)->asic_funcs->invalidate_hdp ? (adev)->asic_funcs->invalidate_hdp((adev), (r)) : \
-	 ((adev)->hdp.funcs->invalidate_hdp ? (adev)->hdp.funcs->invalidate_hdp((adev), (r)) : 0))
+	 ((adev)->hdp.funcs->invalidate_hdp ? (adev)->hdp.funcs->invalidate_hdp((adev), (r)) : (void)0))
 #define amdgpu_asic_need_full_reset(adev) (adev)->asic_funcs->need_full_reset((adev))
 #define amdgpu_asic_init_doorbell_index(adev) (adev)->asic_funcs->init_doorbell_index((adev))
 #define amdgpu_asic_get_pcie_usage(adev, cnt0, cnt1) ((adev)->asic_funcs->get_pcie_usage((adev), (cnt0), (cnt1)))