mm/swap_slots.c: delete meaningless forward declarations

deactivate_swap_slots_cache() and reactivate_swap_slots_cache() are only
called below their implementations.  So these forward declarations are
meaningless and should be removed.

Link: https://lkml.kernel.org/r/20210520134022.1370406-4-linmiaohe@huawei.comSigned-off-by: NMiaohe Lin <linmiaohe@huawei.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/swap_slots.c

@@ -43,8 +43,6 @@ static DEFINE_MUTEX(swap_slots_cache_mutex);
 static DEFINE_MUTEX(swap_slots_cache_enable_mutex);
 
 static void __drain_swap_slots_cache(unsigned int type);
-static void deactivate_swap_slots_cache(void);
-static void reactivate_swap_slots_cache(void);
 
 #define use_swap_slot_cache (swap_slot_cache_active && swap_slot_cache_enabled)
 #define SLOTS_CACHE 0x1