[brcm63xx] add support for 'MAGIC' bcm6348-based board

[brcm63xx] add support for 'MAGIC' bcm6348-based board

I wrote a patch to add 96348SV board (aka MAGIC) support to trunk.
In my case I've found it in a Telsey "Alice W-Gate" router, fairly common
(in the past) in Italy.

I used the board definition (GPIOs, leds, ...) from the Broadcom GPL-2
relased code (here is a mirror: http://beghiero.myftp.org/sorgenti/boardparms.c )

Thanks to KanjiMonster for the support on the IRC channel.

Signed-off-by: Laurento Frittella <laurento.frittella@gmail.com>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@25584 3c298f89-4303-0410-b956-a3cf2f4a3e73