misc: fix integer as NULL pointer warnings

drivers/md/raid10.c:889:17: warning: Using plain integer as NULL pointer
drivers/media/video/cx18/cx18-driver.c:616:12: warning: Using plain integer as NULL pointer
sound/oss/kahlua.c:70:12: warning: Using plain integer as NULL pointer

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/sound/oss/kahlua.c b/sound/oss/kahlua.c
index dfe670f..eb9bc36 100644
--- a/sound/oss/kahlua.c
+++ b/sound/oss/kahlua.c
@@ -67,7 +67,7 @@
 		return 1;
 	
 	mem = ioremap(base, 128);
-	if(mem == 0UL)
+	if (!mem)
 		return 1;
 	map = readw(mem + 0x18);	/* Read the SMI enables */
 	iounmap(mem);