drm: Discard pm_runtime_put() return value

drm: Discard pm_runtime_put() return value

Multiple DRM drivers use the pm_runtime_put() return value for printing
debug or even error messages and all of those messages are at least
somewhat misleading.

Returning an error code from pm_runtime_put() merely means that it has
not queued up a work item to check whether or not the device can be
suspended and there are many perfectly valid situations in which that
can happen, like after writing "on" to the devices' runtime PM "control"
attribute in sysfs for one example.  It also happens when the kernel
has been configured with CONFIG_PM unset.

For this reason, modify all of those drivers to simply discard the
pm_runtime_put() return value which is what they should be doing.

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>
Acked-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Acked-by: Liviu Dudau <liviu.dudau@arm.com>
Link: https://patch.msgid.link/2256082.irdbgypaU6@rafael.j.wysocki