lcs: ensure proper ccw setup

Make sure that all ccws used for writing are initialized with
zeros - especially since the last ccw contains a TIC for which
the unused fields have to be zeros.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>