drm/amd/amdgpu: fix comparison pointer to bool warning in sdma_v5_0.c

Fixes coccicheck warning:

drivers/gpu/drm/amd/amdgpu/sdma_v5_0.c:619:5-11: 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_v5_0.c

@@ -616,7 +616,7 @@ static void sdma_v5_0_enable(struct amdgpu_device *adev, bool enable)
 	u32 f32_cntl;
 	int i;
 
-	if (enable == false) {
+	if (!enable) {
 		sdma_v5_0_gfx_stop(adev);
 		sdma_v5_0_rlc_stop(adev);
 	}