kbuild: Allow for CONFIG_SYS_CONFIG_NAME to be unset

It is possible to have a platform which does not require a board.h file
to build, but today we need an empty one for our generated config.h file
to be valid. Allow for omitting this file if CONFIG_SYS_CONFIG_NAME is
not set.

Signed-off-by: Tom Rini <trini@konsulko.com>
1 file changed