tint: Fix tint and add Kconfig option

Fix the compiler errors with tint, improves the Makefile,
adds Kconfig integration and secondary payload option.

Change-Id: Ia99e30f566d5ccf0d083e52bf174970535daefc5
Signed-off-by: Antonello Dettori <dettori.an@gmail.com>
Reviewed-on: https://review.coreboot.org/14989
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
6 files changed