payloads/external: Rename Makefile.inc to Makefile

These makefiles are not included by anything, so they shouldn't be
named Makefile.inc.  Also, having them all be named 'Makefile' makes
some other consolidation work I'm doing much easier.

Change-Id: I1234539ba6a0a6f47d2eb0c21de3da3607c6b8de
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/14130
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
8 files changed