packet: remove error prone po->running check

Adding snippets from commit 99c07865 ("packet: in packet_do_bind,
test fanout with bind_lock held") which were missed during propagation.

Fixes: 99c07865 ("packet: in packet_do_bind, test fanout with bind_lock held")
Change-Id: I55ae86da82d7b76a3336917c01324ea600ed8e08
Signed-off-by: Ashwanth Goli <ashwanth@codeaurora.org>