arm: Note vendor-required status of certain MACH_TYPE values

In the cases of some boards, a MACH_TYPE number is used which is either
not registered upstream or worse (for functionality) is re-using the
number of a different (or reference) platform instead.  Make sure we
have a comment in these cases.

Cc: Albert ARIBAUD <albert.aribaud@3adev.fr>
Cc: Walter Schweizer <swwa@users.sourceforge.net>
Cc: Stefan Roese <sr@denx.de>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
Acked-by: Stefan Roese <sr@denx.de>
diff --git a/include/configs/udoo.h b/include/configs/udoo.h
index 9610621..90b682e 100644
--- a/include/configs/udoo.h
+++ b/include/configs/udoo.h
@@ -13,8 +13,8 @@
 
 #include "imx6_spl.h"
 
-#define MACH_TYPE_UDOO		4800
-#define CONFIG_MACH_TYPE	MACH_TYPE_UDOO
+/* Provide the MACH_TYPE value that the vendor kernel requires. */
+#define CONFIG_MACH_TYPE		4800
 
 /* Size of malloc() pool */
 #define CONFIG_SYS_MALLOC_LEN		(2 * SZ_1M)