ionic: add private workqueue per-device

ionic: add private workqueue per-device

Instead of using the system's default workqueue, add a private
workqueue for the device to use for its little jobs.  This is
to better support the new work items we will be adding in the
next patches for PF and VF specific jobs, without inundating
the system workqueue in a couple of customer cases where our
devices get scaled out to 100-200 VFs.

Signed-off-by: Brett Creeley <brett.creeley@amd.com>
Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
Link: https://lore.kernel.org/r/20240619003257.6138-4-shannon.nelson@amd.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>