Blackfin arch: put quotes around error to silence a ton of warnings from gcc-4.3

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

diff --git a/arch/blackfin/mach-bf537/include/mach/bf537.h b/arch/blackfin/mach-bf537/include/mach/bf537.h
index 24d5c9d..f194a84 100644
--- a/arch/blackfin/mach-bf537/include/mach/bf537.h
+++ b/arch/blackfin/mach-bf537/include/mach/bf537.h
@@ -133,7 +133,7 @@
 #endif
 
 #ifndef CPU
-#error Unknown CPU type - This kernel doesn't seem to be configured properly
+#error "Unknown CPU type - This kernel doesn't seem to be configured properly"
 #endif
 
 #endif				/* __MACH_BF537_H__  */