ANDROID: add __dev_kfree_skb_irq to virtual_device abi list

Due to the change in commit 06467130 ("Bluetooth: btusb: don't call
kfree_skb() under spin_lock_irqsave()"), __dev_kfree_skb_irq is now
required by the btusb.ko module, so add it to the virtual abi list to
properly export it.

Fixes: 06467130 ("Bluetooth: btusb: don't call kfree_skb() under spin_lock_irqsave()")
Change-Id: Id91e73b52990fa9c3907dcc491e16fadb954e830
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>