USB: Extend and neaten dbg macros

Add format/argument validation for #ifndef DEBUG dbg macro
Neaten dbg macro definitions

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/include/linux/usb/serial.h b/include/linux/usb/serial.h
index 1819396..0a458b8 100644
--- a/include/linux/usb/serial.h
+++ b/include/linux/usb/serial.h
@@ -351,14 +351,11 @@
 
 /* Use our own dbg macro */
 #undef dbg
-#define dbg(format, arg...) \
-	do { \
-		if (debug) \
-			printk(KERN_DEBUG "%s: " format "\n" , __FILE__ , \
-				## arg); \
-	} while (0)
-
-
+#define dbg(format, arg...)						\
+do {									\
+	if (debug)							\
+		printk(KERN_DEBUG "%s: " format "\n", __FILE__, ##arg);	\
+} while (0)
 
 #endif /* __LINUX_USB_SERIAL_H */