staging: unisys: add toolaction to sysfs

Move the proc entry for controlling the toolaction field to sysfs. The field
appears in /sys/devices/platform/visorchipset/install/toolaction.

This field is used to tell s-Par which type of recovery tool action to perform
on the next guest boot-up. The meaning of the value is dependent on the type
of installation software used to commission the guest.

Signed-off-by: Benjamin Romer <benjamin.romer@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>