vxworks.h: Fix build problem introduced by commits 29a4c24d/e9084b23

Signed-off-by: Wolfgang Denk <wd@denx.de>
diff --git a/include/vxworks.h b/include/vxworks.h
index 548e8e8..1633904 100644
--- a/include/vxworks.h
+++ b/include/vxworks.h
@@ -47,7 +47,7 @@
 #endif
 
 #ifndef CONFIG_SYS_VXWORKS_SERVERNAME
-#define CONFIG_SYS_VXWORKS_SERVERNAME srv
+#define CONFIG_SYS_VXWORKS_SERVERNAME	"srv"
 #endif
 
 #endif