avr32: Fix build error caused by include file reshuffling

Various avr32 builds fail:

  arch/avr32/oprofile/backtrace.c:58: error: dereferencing pointer to incomplete type
  arch/avr32/oprofile/backtrace.c:60: error: implicit declaration of function 'user_mode'

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no>
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robert Richter <rric@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: oprofile-list@lists.sf.net
Fixes: f780d89a0e ("sched/headers: Remove <asm/ptrace.h> from ...")
Link: http://lkml.kernel.org/r/1488762357-4500-1-git-send-email-linux@roeck-us.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/avr32/oprofile/backtrace.c

@@ -14,7 +14,7 @@
  */
 
 #include <linux/oprofile.h>
-#include <linux/sched.h>
+#include <linux/ptrace.h>
 #include <linux/uaccess.h>
 
 /* The first two words of each frame on the stack look like this if we have