[MIPS] Use -Werror on subdirectories which build cleanly.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/jazz/Makefile b/arch/mips/jazz/Makefile
index ae4c402..575a944 100644
--- a/arch/mips/jazz/Makefile
+++ b/arch/mips/jazz/Makefile
@@ -3,3 +3,5 @@
 #
 
 obj-y	 	:= irq.o jazzdma.o jazz-platform.o reset.o setup.o
+
+EXTRA_CFLAGS += -Werror