ia64 and mips have separate definitions for siginfo from the
generic one.  Patch them to have the pkey fields.

Note that this is exactly what we did for MPX as well.

[ This fixes a compile error that Ingo was hitting with MIPS when the
  x86 pkeys patch set is applied. ]
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Malat <oss@malat.biz>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-ia64@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20160217181703.E99B6656@viggo.jf.intel.comSigned-off-by: Ingo Molnar <mingo@kernel.org>