USB: musb: make DBG() calls actually depend on CONFIG_USB_MUSB_DEBUG

Enabling CONFIG_USB_MUSB_DEBUG option causes -DDEBUG to be added to gcc's
command line, however the DBG() macro doesn't depend on DEBUG, so that the
debugging messages get printed regardless of the option, and I don't think
that this was intended. Get rid of otherwise unused xprintk() macro and make
DBG() macro directly call pr_debug() which only results in the actual code
generated if DEBUG is defined.

This change makes musb_hdrc.o ~30% less in size with CONFIG_USB_MUSB_DEBUG
disabled (in host mode).
Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/musb/musb_debug.h

@@ -42,11 +42,10 @@
 #define INFO(fmt, args...) yprintk(KERN_INFO, fmt, ## args)
 #define ERR(fmt, args...) yprintk(KERN_ERR, fmt, ## args)
 
-#define xprintk(level, facility, format, args...) do { \
-	if (_dbg_level(level)) { \
-		printk(facility "%s %d: " format , \
-				__func__, __LINE__ , ## args); \
-	} } while (0)
+#define DBG(level, format, args...) do { \
+	if (_dbg_level(level)) \
+		pr_debug("%s %d: " format, __func__, __LINE__, ## args); \
+	} while (0)
 
 extern unsigned musb_debug;
 
@@ -55,8 +54,6 @@ static inline int _dbg_level(unsigned l)
 	return musb_debug >= l;
 }
 
-#define DBG(level, fmt, args...) xprintk(level, KERN_DEBUG, fmt, ## args)
-
 extern const char *otg_state_string(struct musb *);
 
 #ifdef CONFIG_DEBUG_FS