drivers/w1/masters: remove CONFIG_EXPERIMENTAL

This config item has not carried much meaning for a while now and is
almost always enabled by default. As agreed during the Linux kernel
summit, remove it.

CC: Andrew Morton <akpm@linux-foundation.org>
CC: Paul Walmsley <paul@pwsan.com>
CC: Felipe Balbi <balbi@ti.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>