staging: unisys: move installer to sysfs and split fields

The installer entry in /proc/visorchipset/installer was composed of three
separate fields as one entry. This patch removes the proc entry and associated
functions, and creates new fields with distinct entries under sysfs in the
visorchipset/install directory. The fields are:

	textid: used to send the ID of a string that should be displayed on
		s-Par's automatic installation progress screen. Setting this
		field when not in installation mode (boottotool was set on
		the previous guest boot) has no effect.

	remaining_steps: used to set the value of the progress bar on the
		s-Par automatic installation progress screen. This field has
		no effect if not in installation mode.

	error: used to send the ID of a string that should be displayed on
		s-Par's automatic installation progress screen when an error
		is encountered during installation. This field has no effect
		if not in installation mode.

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