ACPI: AC: fix some coding style issues

Fix some coding style issues reported by checkpatch.pl, including the
following types:

ERROR: "foo * bar" should be "foo *bar"
ERROR: code indent should use tabs where possible
WARNING: Block comments use a trailing */ on a separate line
WARNING: braces {} are not necessary for single statement blocks
WARNING: void function return statements are not generally useful
WARNING: CVS style keyword markers, these will _not_ be updated

Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>