cimx sb700: change Platform.h to remove some warnings

TRACE has redefined warnings in src/southbridge/amd/cimx/sb700/Platform.h,
so we do some changes to remove such warnings.

Change-Id: I24979e08b83434f91a8fa37cd9f16303fa0b298d
Signed-off-by: Siyuan Wang <SiYuan.Wang@amd.com>
Signed-off-by: Siyuan Wang <wangsiyuanbuaa@gmail.com>
Reviewed-on: http://review.coreboot.org/1499
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marcj303@gmail.com>

src/southbridge/amd/cimx/sb700/Platform.h

@@ -60,6 +60,9 @@ void    TraceCode ( UINT32 Level, UINT32 Code);
 #define TRACECODE(Arguments)
 #endif
 #else
+	#ifdef TRACE
+		#undef TRACE
+	#endif
 	#if CONFIG_REDIRECT_SBCIMX_TRACE_TO_SERIAL
 		#define TRACE(Arguments) printk Arguments
 	#else