branch tracer, intel-iommu: fix build with CONFIG_BRANCH_TRACER=y

Fix the branch tracer barfing on comma statements within if ()
statements.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

include/linux/compiler.h

@@ -115,7 +115,9 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
  * "Define 'is'", Bill Clinton
  * "Define 'if'", Steven Rostedt
  */
-#define if(cond) if (__builtin_constant_p((cond)) ? !!(cond) :		\
+#define if(cond, ...) __trace_if( (cond , ## __VA_ARGS__) )
+#define __trace_if(cond) \
+	if (__builtin_constant_p((cond)) ? !!(cond) :			\
 	({								\
 		int ______r;						\
 		static struct ftrace_branch_data			\