move platform specific base-files into target/linux/<targetname>

include/kernel.mk

package/base-files/Makefile

target/linux/ar7-2.4/base-files.mk

target/linux/ar7-2.4/base-files/bin/firstboot

target/linux/ar7-2.4/base-files/etc/config/network

target/linux/ar7-2.4/base-files/etc/init.d/adam2

target/linux/ar7-2.4/base-files/etc/preinit

target/linux/ar7-2.4/base-files/sbin/mount_root

target/linux/ar7-2.4/src/adam2patcher.c

target/linux/aruba-2.6/base-files/etc/config/network

target/linux/au1000-2.6/base-files/etc/config/network

target/linux/au1000-2.6/base-files/sbin/mount_root

target/linux/brcm-2.4/base-files.mk

target/linux/brcm-2.4/base-files/bin/firstboot

target/linux/brcm-2.4/base-files/etc/diag.sh

target/linux/brcm-2.4/base-files/etc/init.d/done

target/linux/brcm-2.4/base-files/etc/init.d/netconfig

target/linux/brcm-2.4/base-files/etc/preinit

target/linux/brcm-2.4/base-files/sbin/hotplug.failsafe

target/linux/brcm-2.4/base-files/sbin/mount_root