driver core: replace open-coded device_lock_assert()

Using the right wrapper makes it easier to associate this assert
statement with the device_[un]lock() helpers.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Link: https://lore.kernel.org/r/20210512141054.2180373-1-jwi@linux.ibm.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>