remove CONFIG_KMOD from drivers

Straight forward conversions to CONFIG_MODULE; many drivers
include <linux/kmod.h> conditionally and then don't have any
other conditional code so remove it from those.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: video4linux-list@redhat.com
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: linux-ppp@vger.kernel.org
Cc: dm-devel@redhat.com
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>