o Add simple usage example.
o Fix up unit handling (k, M. G).
o Use correct size limit for setup string.
o Remove pointless printk message.
o Fix mtdblock to not allocate a read-modify-write buffer for CAP_RAM
  devices (and fail to do so, returning an error).
Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>