#761 coreboot doesn't build

System info: - Linux parabola 5.4.85-gnu-1-lts #1 SMP Wed, 23 Dec 2020 x86_64 GNU/Linux - gcc version 10.2.0 ### Where `coreboot/{REV}/{REV}/util/cbfstool/lz4/lib/lz4frame.c:1092` ### Why Compiler is throwing`implicit-fallthrough`. ### Fix 1. Add `-Werror=-Wimplicit-fallthrough=3` to the `make` command at `resources/scripts/helpers/build/module/coreboot:44`. 2. Add `/* Falls through. */` to `coreboot/{REV}/{REV}/util/cbfstool/lz4/lib/lz4frame.c:1094`. (Fixed in coreboot upstream)