drm/amd/amdgpu: fix comparison pointer to bool warning in sdma_v4_0.c

Fixes coccicheck warning:

drivers/gpu/drm/amd/amdgpu/sdma_v4_0.c:1003:4-9: WARNING: Comparison to bool
drivers/gpu/drm/amd/amdgpu/sdma_v4_0.c:1083:5-11: WARNING: Comparison to bool
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Zheng Bin <zhengbin13@huawei.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/sdma_v4_0.c

@@ -1000,7 +1000,7 @@ static void sdma_v4_0_page_stop(struct amdgpu_device *adev)
 		sdma[i] = &adev->sdma.instance[i].page;
 
 		if ((adev->mman.buffer_funcs_ring == sdma[i]) &&
-			(unset == false)) {
+			(!unset)) {
 			amdgpu_ttm_set_buffer_funcs_status(adev, false);
 			unset = true;
 		}
@@ -1089,7 +1089,7 @@ static void sdma_v4_0_enable(struct amdgpu_device *adev, bool enable)
 	u32 f32_cntl;
 	int i;
 
-	if (enable == false) {
+	if (!enable) {
 		sdma_v4_0_gfx_stop(adev);
 		sdma_v4_0_rlc_stop(adev);
 		if (adev->sdma.has_page_queue)