move most of the x86 image generation options to the main file

Signed-off-by: Imre Kaloz <kaloz@openwrt.org>



git-svn-id: svn://svn.openwrt.org/openwrt/trunk@39206 3c298f89-4303-0410-b956-a3cf2f4a3e73
virtualbox emulates the e1000 for a long time now

Signed-off-by: Imre Kaloz <kaloz@openwrt.org>


git-svn-id: svn://svn.openwrt.org/openwrt/trunk@39207 3c298f89-4303-0410-b956-a3cf2f4a3e73