kernel: reduce spurious rebuilds of simple kmod-* packages

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt@37403 3c298f89-4303-0410-b956-a3cf2f4a3e73
kernel: make kmod-sched depend on kmod-ipt-core

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt@37404 3c298f89-4303-0410-b956-a3cf2f4a3e73