contrib: dracut: parse-zfs: drop initqueue-finished for i/f

The switch was released in dracut 009 in March 2011,
we can safely get rid of the compatibility hook

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #13291