ACPI: PM: Improve kerneldoc comments for suspend and hibernation functions

This patch enhances the documentation for the ACPI power management
functions related to system suspend and hibernation.

This includes the use of kernel-doc style comments which provide
developers with clearer guidance on the usage and expectations of
these functions.

Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
[ rjw: Subject edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>