common: move BUILD_BUG_ON define to common.h

see discussion also here:
http://patchwork.ozlabs.org/patch/75309/

Signed-off-by: Heiko Schocher <hs@denx.de>
cc: Wolfgang Denk <wd@denx.de>
cc: Holger Brunck <holger.brunck@keymile.com>
diff --git a/include/common.h b/include/common.h
index 6061643..1572791 100644
--- a/include/common.h
+++ b/include/common.h
@@ -137,6 +137,9 @@
 #define BUG_ON(condition) do { if (unlikely((condition)!=0)) BUG(); } while(0)
 #endif /* BUG */
 
+/* Force a compilation error if condition is true */
+#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
+
 typedef void (interrupt_handler_t)(void *);
 
 #include <asm/u-boot.h> /* boot information for Linux kernel */