fs/proc/task_mmu.c: remove duplicated include files

Removed duplicated include files <linux/ptrace.h> and <linux/seq_file.h> in
fs/proc/task_mmu.c.
Signed-off-by: Huang Weiyi <weiyi.huang@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/proc/task_mmu.c

@@ -5,11 +5,9 @@
 #include <linux/highmem.h>
 #include <linux/ptrace.h>
 #include <linux/pagemap.h>
-#include <linux/ptrace.h>
 #include <linux/mempolicy.h>
 #include <linux/swap.h>
 #include <linux/swapops.h>
-#include <linux/seq_file.h>
 
 #include <asm/elf.h>
 #include <asm/uaccess.h>