misc/pvpanic : grouping ACPI related stuff

Grouping ACPI related stuff and make preparation to break
the ACPI dependency w/o any functional change.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Peng Hao <peng.hao2@zte.com.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>