[coreboot-gerrit] Patch merged into coreboot/master: payloads/external/Makefile.inc: Don't rebuild SeaBIOS every time

the following patch was just integrated into master:
commit 342cf7f6a4f63862a7b043b6c56fd3f5f3d7e500
Author: Martin Roth 
Date:   Mon Mar 7 22:04:01 2016 -0700

payloads/external/Makefile.inc: Don't rebuild SeaBIOS every time

Currently, if SeaBIOS is set as the payload, it gets rebuilt every
    single time we do a build.

Change it to re-build just when there’s a config change.

Change-Id: Ib141f2cbf8796d449172432bb30fa4806cf90328
    Signed-off-by: Martin Roth 
    Reviewed-on: https://review.coreboot.org/13948
    Tested-by: build bot (Jenkins)
    Reviewed-by: Stefan Reinauer

See https://review.coreboot.org/13948 for details.

-gerrit