[Blackfin] arch: add missing __user marking to ss_sp member of signalstack and a few userspace system functions

Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

diff --git a/include/asm-blackfin/signal.h b/include/asm-blackfin/signal.h
index 0250429..87951d2 100644
--- a/include/asm-blackfin/signal.h
+++ b/include/asm-blackfin/signal.h
@@ -143,7 +143,7 @@
 #endif				/* __KERNEL__ */
 
 typedef struct sigaltstack {
-	void *ss_sp;
+	void __user *ss_sp;
 	int ss_flags;
 	size_t ss_size;
 } stack_t;