ieee1394: safer definition of empty macros

A deactivated macro, defined as "#define foo(bar)", will result in
silent corruption if somebody forgets a semicolon after a call to foo.
Replace it by "#define foo(bar) do {} while (0)" which will reveal any
respective syntax errors.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
diff --git a/drivers/ieee1394/ieee1394_types.h b/drivers/ieee1394/ieee1394_types.h
index a8de375..9803aaa 100644
--- a/drivers/ieee1394/ieee1394_types.h
+++ b/drivers/ieee1394/ieee1394_types.h
@@ -41,7 +41,7 @@
 #define HPSB_VERBOSE(fmt, args...)	HPSB_PRINT(KERN_DEBUG, fmt , ## args)
 #define HPSB_DEBUG_TLABELS
 #else
-#define HPSB_VERBOSE(fmt, args...)
+#define HPSB_VERBOSE(fmt, args...)	do {} while (0)
 #endif
 
 #ifdef __BIG_ENDIAN