[netdrvr b44] include linux/dma-mapping.h to eliminate warning

drivers/net/b44.c

@@ -19,6 +19,7 @@
 #include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/version.h>
+#include <linux/dma-mapping.h>
 
 #include <asm/uaccess.h>
 #include <asm/io.h>