microblaze_mmu_v2: Update signal returning address

Signed-off-by: Michal Simek <monstr@monstr.eu>
diff --git a/arch/microblaze/kernel/signal.c b/arch/microblaze/kernel/signal.c
index 3cdcbfe..4c0e652 100644
--- a/arch/microblaze/kernel/signal.c
+++ b/arch/microblaze/kernel/signal.c
@@ -388,7 +388,15 @@
 	case -ERESTARTNOINTR:
 do_restart:
 		/* offset of 4 bytes to re-execute trap (brki) instruction */
+#ifndef CONFIG_MMU
 		regs->pc -= 4;
+#else
+		/* offset of 8 bytes required = 4 for rtbd
+		   offset, plus 4 for size of
+			"brki r14,8"
+		   instruction. */
+		regs->pc -= 8;
+#endif
 		break;
 	}
 }