includecheck fix: include/linux, page_cgroup.h

fix the following 'make includecheck' warning:

  include/linux/page_cgroup.h: linux/swap.h is included more than once.
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>

include/linux/page_cgroup.h

@@ -105,14 +105,14 @@ static inline void __init page_cgroup_init_flatmem(void)
 
 #endif
 
-#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
 #include <linux/swap.h>
+
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
 extern unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id);
 extern unsigned short lookup_swap_cgroup(swp_entry_t ent);
 extern int swap_cgroup_swapon(int type, unsigned long max_pages);
 extern void swap_cgroup_swapoff(int type);
 #else
-#include <linux/swap.h>
 
 static inline
 unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id)