powerpc: fix 8xx and 82xx type-punning warnings with GCC 4.7

C99's strict aliasing rules are insane to use in low-level code such as a
bootloader, but as Wolfgang has rejected -fno-strict-aliasing in the
past, add a union so that 16-bit accesses can be performed.

Compile-tested only.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Acked-by: Wolfgang Denk <wd@denx.de>
diff --git a/include/commproc.h b/include/commproc.h
index 7ca28c8..6959905 100644
--- a/include/commproc.h
+++ b/include/commproc.h
@@ -127,6 +127,7 @@
 */
 #define PROFF_SCC1	((uint)0x0000)
 #define PROFF_IIC	((uint)0x0080)
+#define PROFF_REVNUM	((uint)0x00b0)
 #define PROFF_SCC2	((uint)0x0100)
 #define PROFF_SPI	((uint)0x0180)
 #define PROFF_SCC3	((uint)0x0200)