By converting to the restart_notifier mechanism for restart, we allow
for other mechanisms, like the watchdog, to be used for restart in the
case where PS_HOLD has failed to reset the chip.

Since this mechanism may be one of several mechanisms registered, change
the post-ps_hold write timeout to be a more reasonable 1 second instead
of 10 seconds.

Choose priority 128, as according to documentation, this mechanism "is
sufficient to restart the entire system".
Tested-by: Pramod Gurav <pramod.gurav@smartplayin.com>
Signed-off-by: Josh Cartwright <joshc@codeaurora.org>
Acked-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>