packagegroup: fix a comment regarding PACKAGE_ARCH
packagegroups whose dependencies are affected by MACHINE_FEATURES
need to be marked as MACHINE_ARCH *before* inheriting the
packagegroup class, not after.
This has changed in commit 9c826962ec8f
("packagegroup: Make allarch inherit conditional"),
commit 4f3f34deafe4 in poky but the comment here
wasn't updated at the time.
Signed-off-by: André Draszik <andre.draszik@jci.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>