Input: synaptics-rmi4 - destroy F54 poller workqueue when removing

Input: synaptics-rmi4 - destroy F54 poller workqueue when removing

BugLink: https://bugs.launchpad.net/bugs/1853915
commit ba60cf9f78f0d7c8e73c7390608f7f818ee68aa0 upstream.

The driver forgets to destroy workqueue in remove() similarly to what is
done when probe() fails. Add a call to destroy_workqueue() to fix it.

Since unregistration will wait for the work to finish, we do not need to
cancel/flush the work instance in remove().

Signed-off-by: Chuhong Yuan <hslester96@gmail.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20191114023405.31477-1-hslester96@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>