habanalabs: don't free phys_pg_pack inside lock

Freeing phys_pg_pack includes calling to scrubbing functions of the
device's memory, taking locks and possibly even calling reset.

This is not something that should be done while holding a device-wide
spinlock.

Therefore, save the relevant objects on a local linked-list and after
releasing the spinlock, traverse that list and free the phys_pg_pack
objects.

Signed-off-by: Oded Gabbay <ogabbay@kernel.org>