Squashed commit of the following:
drivers/: Run tools/nxstyle against all drivers/*.c.
boards/boardctl.c: Add new boardctl() command, BOARDIOC_MKRD, that can be used to create a RAM disk. This will replace the illegal call to ramdisk_register() currently used by NSH.
drivers/mkrd.c: Add wrapper around ramdisk_register() for creating a proper ramdisk.