zcache-main.c: remove left over 2nd arguments of k[un]map_atomic()

from commit: dba39e539615aad207f8796c852dfee04fb0521a

Signed-off-by: Paul Reioux <reioux@gmail.com>
zram swap: remove auto zram swap initialization

Signed-off-by: Paul Reioux <reioux@gmail.com>