brd: fix comment on initial device creation

If 'rd_nr' param was not specified, 16 (can be adjusted via
CONFIG_BLK_DEV_RAM_COUNT) devices would be created by default
but comment said 1. Fix it.
Signed-off-by: NNamhyung Kim <namhyung@gmail.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

drivers/block/brd.c

@@ -571,10 +571,10 @@ static int __init brd_init(void)
 	 *
 	 * (1) if rd_nr is specified, create that many upfront, and this
 	 *     also becomes a hard limit.
-	 * (2) if rd_nr is not specified, create 1 rd device on module
-	 *     load, user can further extend brd device by create dev node
-	 *     themselves and have kernel automatically instantiate actual
-	 *     device on-demand.
+	 * (2) if rd_nr is not specified, create CONFIG_BLK_DEV_RAM_COUNT
+	 *     (default 16) rd device on module load, user can further
+	 *     extend brd device by create dev node themselves and have
+	 *     kernel automatically instantiate actual device on-demand.
 	 */
 
 	part_shift = 0;