'factory' and 'sysupgrade' did not make much sense. A discussion
with jow convinced me that .trx results in a helpdesk disaster.
So I decided to use '.bin' for normal bin-headers and '.noheader.bin'
for the trx-v2 image.
I fixed the wiki accordingly.
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@22013 3c298f89-4303-0410-b956-a3cf2f4a3e73
