[coreboot] [PATCH] filo kconfig

[baiyin cai]

hi all,
   i updated an new patch for filo kconfig. which involves following things:
   1. Using make -C command to replace the old method which use filo/kconfig
to load libpayload .config file.
       it make the code seems much simpler.
   2. The latest filo kconfig did only printf an message the reminder that
lib.config is missing. In
       the new patch,filo will load the default config for libpayload.
   3. Fixing the bug which cause the libpayload building each time the filo
is buiding.

Any consideration is welcome about these filo kconfig.

Signed-off-by: Cai Bai Yin