LinuxKPI: skbuff: dev_kfree_skb_irq() and improvements

While it is currently unclear if we will have to defer work in
dev_kfree_skb_irq() to call dev_kfree_skb().
We only have one caller which seems to be fine on FreeBSD by calling
it directly for now.

While here shortcut skb_put()/skb_put_data() saving us work if there
are no adjustments to do.
Also adjust the logging in skb_is_gso() to avoid getting spammed by it.

Sponsored by: The FreeBSD Foundation
MFC after: 3 days