fwcutter: Add firmware 6.30.163.46

This firmware version can be extracted from the GPL tarball for the ASUS
GPL code for the RT-AC66U 802.11ac Dual-Band Wireless-AC1750 Gigabit Router.

I believe this to be the first instance of 802.11ac firmware for Broadcom
hardware. The firmware is version 784.2.

Note: The http://www.lwfinger.com/broadcom-wl-6.30.163.46.tar.bz2 is the URL
of the extracted apsta binary. The full GPL package is at
http://dlcdnet.asus.com/pub/ASUS/wireless/RT-AC66U/GPL_RT_AC66U_3004372.zip.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Michael Buesch <m@bues.ch>
Fix memset size argument error.

Detected by gcc:

  md5.c: In function ‘MD5Final’:
  md5.c:245:26: warning: argument to ‘sizeof’ in ‘memset’ call is the same expression as the destination; did you mean to dereference it? [-Wsizeof-pointer-memaccess]

Signed-off-by: Michael Buesch <m@bues.ch>