list: remove duplicated list.h ...

We accidently have two list implementations in the tree:
include/list.h and include/linux/list.h. This patch moves
the latter (newer one) to include/linux/list.h.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Add notifier framework ...

This is loosely based on the Linux notifier framework, but
stripped down to the bare minimum.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>