layer.conf: set compatibility for hardknott
layer.conf: set compatibility for hardknott

Signed-off-by: Andrea Adami <58a22b0beb8ec13ae546a060c8b4c576f22f6153@gmail.com>
Signed-off-by: Paul Eggleton <14bab6e4283855b62f8d6e7a53c272fde04418c0@bluelightning.org>

bluelightning/meta-handheld,bluelightning/meta-handheld