include: delete include/linux/config.h

Linux Kernel abolished include/linux/config.h long time ago.
(around version v2.6.18..v2.6.19)

We don't need to provide Linux copatibility any more.

This commit deletes include/linux/config.h
and fixes source files not to include this.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>