drm/amdgpu/dpm: don't add pwm attributes if DPM is disabled

PWM fan control is only available with DPM.  There is no non-DPM
support on amdgpu, so we should never get a crash here because
the sysfs nodes would never be created in the first place. Add the
check just in case to be on the safe side.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
index efed115..ed2bbe5 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
@@ -294,10 +294,14 @@
 	struct amdgpu_device *adev = dev_get_drvdata(dev);
 	umode_t effective_mode = attr->mode;
 
-	/* Skip limit attributes if DPM is not enabled */
+	/* Skip attributes if DPM is not enabled */
 	if (!adev->pm.dpm_enabled &&
 	    (attr == &sensor_dev_attr_temp1_crit.dev_attr.attr ||
-	     attr == &sensor_dev_attr_temp1_crit_hyst.dev_attr.attr))
+	     attr == &sensor_dev_attr_temp1_crit_hyst.dev_attr.attr ||
+	     attr == &sensor_dev_attr_pwm1.dev_attr.attr ||
+	     attr == &sensor_dev_attr_pwm1_enable.dev_attr.attr ||
+	     attr == &sensor_dev_attr_pwm1_max.dev_attr.attr ||
+	     attr == &sensor_dev_attr_pwm1_min.dev_attr.attr))
 		return 0;
 
 	/* Skip fan attributes if fan is not present */