ACPI: sysfs: fix some coding style issues

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

WARNING: Missing a blank line after declarations
WARNING: Block comments should align the * on each line
ERROR: open brace '{' following function definitions go on the next line

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