ipq806x: unset filesystem specific build command by default
Initialise the filesystem specific build command. Otherwise it will be
unintended inherit to following images and will cause a wrong image
format.
The issue is around for ages but was only recently triggered due to the
added support for the Openmesh a42.
Fixes: FS#1276
Signed-off-by: Mathias Kresin <[email protected]>
Mathias Kresin