irq-forward: use global workqueue to clean up

This fixes a null dereference during cleanup as the custom workqueue was
never initialized.

BUG=None
TEST=Manually verify no crash on crosvm-direct shutdown

Change-Id: Iece47c4055583a19a8a4ee1c8bb249c17767e162
Signed-off-by: David Stevens <stevensd@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/2885403
Reviewed-by: Tomasz Jeznach <tjeznach@chromium.org>
1 file changed