staging: bcm2835-audio: fix empty-body warning

gcc-7 warns about debug statements being left out here:

drivers/staging/bcm2835-audio/bcm2835-vchiq.c: In function 'bcm2835_audio_set_ctls':
drivers/staging/bcm2835-audio/bcm2835-vchiq.c:572:54: error: suggest braces around empty body in an 'else' statement [-Werror=empty-body]

It's better to use no_printk(), which has the added advantage of checking
the format strings.

Fixes: 23b028c871e1 ("staging: bcm2835-audio: initial staging submission")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/bcm2835-audio/bcm2835-vchiq.c

@@ -50,9 +50,9 @@
 #define LOG_DBG( fmt, arg... )   pr_info( "%s:%d " fmt, __func__, __LINE__, ##arg)
 #else
 #define LOG_ERR( fmt, arg... )   pr_err( "%s:%d " fmt, __func__, __LINE__, ##arg)
-#define LOG_WARN( fmt, arg... )
-#define LOG_INFO( fmt, arg... )
-#define LOG_DBG( fmt, arg... )
+#define LOG_WARN( fmt, arg... )	 no_printk(fmt, ##arg)
+#define LOG_INFO( fmt, arg... )	 no_printk(fmt, ##arg)
+#define LOG_DBG( fmt, arg... )	 no_printk(fmt, ##arg)
 #endif
 
 struct bcm2835_audio_instance {