USB: core: Discard pm_runtime_put() return value

USB: core: Discard pm_runtime_put() return value

To allow the return type of pm_runtime_put() to be changed to void in the
future, modify usb_autopm_put_interface_async() to discard the return
value of pm_runtime_put().

That value is merely used in a debug comment printed by the function in
question and it is not a particularly useful piece of information
because pm_runtime_put() does not guarantee that the device will be
suspended even if it successfully queues up a work item to check
whether or not the device can be suspended.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/5058509.GXAFRqVoOG@rafael.j.wysocki