This reverts commit 2b074654b0.
Due to popular demand, I've decided to revert this commit after
deliberating with Petr. This means that 19.07 will ship ath79 binary
images after all.
We do however consider the ath79 target on Kernel 4.14 in the 19.07
branch to be beta quality at best.
Acked-by: Petr Štetiar <ynezz@true.cz>
Signed-off-by: Jo-Philipp Wich <jo@mein.io>