iwlwifi: dvm: don't send zeroed LQ cmd

iwlwifi: dvm: don't send zeroed LQ cmd

commit 63b77bf489881747c5118476918cc8c29378ee63 upstream.

When the stations are being restored because of unassoc
RXON, the LQ cmd may not have been initialized because it
is initialized only after association.
Sending zeroed LQ_CMD makes the fw unhappy: it raises
SYSASSERT_2078.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
[move zero_lq and make static const]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>