staging: vt6656: Fix pairwise key for non station modes

patch 'vnt_set_keymode don't save pairwise key entry' caused
a slight regression in access point mode

Only don't save in station mode.

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>