staging: unisys: add acpi pnp driver

According to Unisys, another OS detects the PNP0A07 as the auto load
device.  We can also do this in the linux kernel by simply converting the
driver over to the ACPI driver model.

Notes: This changes the usage of __init and it had to be removed from some
functions to avoid a !__init function calling an __init function.
Additionally I also cleaned up the headers in visorchipset.c since I was
adding a header file.

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