ALSA: korg1212: fix if-statement empty body warnings

Fix gcc warnings when -Wextra is used by using an empty do-while
block instead of <nothing>.  Fixes these build warnings:

../sound/pci/korg1212/korg1212.c:674:44: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
../sound/pci/korg1212/korg1212.c:708:43: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
../sound/pci/korg1212/korg1212.c:730:43: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
../sound/pci/korg1212/korg1212.c:853:43: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
../sound/pci/korg1212/korg1212.c:1013:44: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
../sound/pci/korg1212/korg1212.c:1035:43: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
../sound/pci/korg1212/korg1212.c:1052:43: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
../sound/pci/korg1212/korg1212.c:1066:43: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
../sound/pci/korg1212/korg1212.c:1087:43: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
../sound/pci/korg1212/korg1212.c:1094:43: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
../sound/pci/korg1212/korg1212.c:1208:43: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
../sound/pci/korg1212/korg1212.c:2360:102: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/91fb1e97-a773-5790-3f65-8198403341e1@infradead.orgSigned-off-by: NTakashi Iwai <tiwai@suse.de>

sound/pci/korg1212/korg1212.c

@@ -30,7 +30,7 @@
 #if K1212_DEBUG_LEVEL > 0
 #define K1212_DEBUG_PRINTK(fmt,args...)	printk(KERN_DEBUG fmt,##args)
 #else
-#define K1212_DEBUG_PRINTK(fmt,...)
+#define K1212_DEBUG_PRINTK(fmt,...)	do { } while (0)
 #endif
 #if K1212_DEBUG_LEVEL > 1
 #define K1212_DEBUG_PRINTK_VERBOSE(fmt,args...)	printk(KERN_DEBUG fmt,##args)