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

Fixes coccicheck warning:

drivers/gpu/drm/amd/amdgpu/si.c:1342:5-10: 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/si.c

@@ -1339,7 +1339,7 @@ static void si_vga_set_state(struct amdgpu_device *adev, bool state)
 	uint32_t temp;
 
 	temp = RREG32(CONFIG_CNTL);
-	if (state == false) {
+	if (!state) {
 		temp &= ~(1<<0);
 		temp |= (1<<1);
 	} else {