ARC: unbork FPU save/restore

Fixes: 2ab402dfd65d15a4b2 "ARC: make start_thread() out-of-line"
CC: <stable@vger.kernel.org>  #3.16
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
diff --git a/arch/arc/include/asm/processor.h b/arch/arc/include/asm/processor.h
index 08fbe2e..210fe97 100644
--- a/arch/arc/include/asm/processor.h
+++ b/arch/arc/include/asm/processor.h
@@ -18,6 +18,15 @@
 
 #include <asm/ptrace.h>
 
+#ifdef CONFIG_ARC_FPU_SAVE_RESTORE
+/* These DPFP regs need to be saved/restored across ctx-sw */
+struct arc_fpu {
+	struct {
+		unsigned int l, h;
+	} aux_dpfp[2];
+};
+#endif
+
 /* Arch specific stuff which needs to be saved per task.
  * However these items are not so important so as to earn a place in
  * struct thread_info