drm/imagination: Discard pm_runtime_put() return value

The Imagination DRM driver defines pvr_power_put() to pass the return
value of pm_runtime_put() to the caller, but then it never uses the
return value of pvr_power_put().

Modify pvr_power_put() to discard the pm_runtime_put() return value and
change its return type to void.

No intentional functional impact.

This will facilitate a planned change of the pm_runtime_put() return
type to void in the future.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Matt Coster <matt.coster@imgtec.com>
Link: https://patch.msgid.link/8642685.T7Z3S40VBb@rafael.j.wysocki

Author: rafaeljw

drivers/gpu/drm/imagination/pvr_power.h

@@ -30,12 +30,12 @@ pvr_power_get(struct pvr_device *pvr_dev)
 	return pm_runtime_resume_and_get(drm_dev->dev);
 }
 
-static __always_inline int
+static __always_inline void
 pvr_power_put(struct pvr_device *pvr_dev)
 {
 	struct drm_device *drm_dev = from_pvr_device(pvr_dev);
 
-	return pm_runtime_put(drm_dev->dev);
+	pm_runtime_put(drm_dev->dev);
 }
 
 int pvr_power_domains_init(struct pvr_device *pvr_dev);