payloads: Force sub-make runs for in-tree payloads

The sub-process calls break make's dependency tracking, hence we have
to always perform the calls if we want to allow automatic, incremental
builds.

We let each rule depend on a new, phony target `force-payload`. It has
roughly the same effect as tagging all the targets as phony, but doing
so would feel wrong as some of them are actual files.

Change-Id: I1bc2406db371e8dddbfdf71f68a6665a5b558f5e
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/47638
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

0 files changed, 0 insertions, 0 deletions