drivers/amdgpu: Use canonical form in branch predicates

Found-by: Coccinelle
Signed-off-by: Edward O'Callaghan <funfunctor@folklore1984.net>
Reviewed-by: Tom St Denis <tom.stdenis@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/amd/amdgpu/cik_sdma.c b/drivers/gpu/drm/amd/amdgpu/cik_sdma.c
index 6507a7e..c1eedc4 100644
--- a/drivers/gpu/drm/amd/amdgpu/cik_sdma.c
+++ b/drivers/gpu/drm/amd/amdgpu/cik_sdma.c
@@ -354,7 +354,7 @@
 	u32 me_cntl;
 	int i;
 
-	if (enable == false) {
+	if (!enable) {
 		cik_sdma_gfx_stop(adev);
 		cik_sdma_rlc_stop(adev);
 	}