<config.h> is per-board config file, which is only allowed for old
boards.

For new boards, the top Makefile creates an empty include/config.h

kvx does not have config.h, so #include <config.h> is useless.

Also, remove meaningless board-$(CONFIG_GENERIC).

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-By: Clement Leger <cleger@kalray.eu>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>