sconfig: Fix build dependencies

In some cases the build system tried to build main.c before
copying the various "shipped" files (lex/yacc output) where
the place the compiler expects them.

Make the dependency explicit.

Change-Id: Iacef5292aadb9fe7bc967aa4ab5ee6c9fe4df3d7
Signed-off-by: Patrick Georgi <patrick@georgi-clan.de>
Reviewed-on: http://review.coreboot.org/5510
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
1 file changed