Fix tracing compilation on SMM enabled targets.

Disallow tracing while in SMM.

Change-Id: Icde17629bb06a615cc48f017fd0cd1f7b720e62d
Signed-off-by: Rudolf Marek <r.marek@assembler.cz>
Reviewed-on: http://review.coreboot.org/1503
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marcj303@gmail.com>

src/include/trace.h

@@ -29,7 +29,7 @@
 
 #else /* !__PRE_RAM__ */
 
-#if CONFIG_TRACE
+#if CONFIG_TRACE && !defined(__SMM__)
 
 void __cyg_profile_func_enter( void *, void * )
 				 __attribute__ ((no_instrument_function));