PM: hibernate: Clean up non-kernel-doc comments

Address the following W=1 kernel build warning:

kernel/power/swap.c:120: warning: This comment starts with '/**', but
isn't a kernel-doc comment. Refer
Documentation/doc-guide/kernel-doc.rst.
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

kernel/power/swap.c

@@ -89,7 +89,7 @@ struct swap_map_page_list {
 	struct swap_map_page_list *next;
 };
 
-/**
+/*
  *	The swap_map_handle structure is used for handling swap in
  *	a file-alike way
  */
@@ -117,7 +117,7 @@ struct swsusp_header {
 
 static struct swsusp_header *swsusp_header;
 
-/**
+/*
  *	The following functions are used for tracing the allocated
  *	swap pages, so that they can be freed in case of an error.
  */
@@ -171,7 +171,7 @@ static int swsusp_extents_insert(unsigned long swap_offset)
 	return 0;
 }
 
-/**
+/*
  *	alloc_swapdev_block - allocate a swap page and register that it has
  *	been allocated, so that it can be freed in case of an error.
  */
@@ -190,7 +190,7 @@ sector_t alloc_swapdev_block(int swap)
 	return 0;
 }
 
-/**
+/*
  *	free_all_swap_pages - free swap pages allocated for saving image data.
  *	It also frees the extents used to register which swap entries had been
  *	allocated.