ice: Unbind the workqueue

The ice workqueue doesn't seem to rely on any CPU locality and should
therefore be able to run on any CPU. In practice this is already
happening through the unbound ice_service_timer that may fire anywhere
and queue the workqueue accordingly to any CPU.

Make this official so that the ice workqueue is only ever queued to
housekeeping CPUs on nohz_full.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>