The x86 image includes the modules out of ata-core and scsi-core
directly in the kernel image. Do not depend on these packages, because
they are not build in a x86 image.
This fixes#6873
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@20346 3c298f89-4303-0410-b956-a3cf2f4a3e73