ixp4xx: update Gateworks Cambria board support

ixp4xx: update Gateworks Cambria board support

Several new features for newer boards:
 - add irq mapping for additional devices
 - add platform data for i2c bus to SFP modules
 - add additional UARTs present on some boards
 - increased R/W delay for expansion bus UARTs
 - add additional LEDs present on some boards
 - add GPIO exports and configuration
 - add ENET switch config present on some boards
 - add support for GSC present on some boards
 - added per model setup support for newer boards

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@33644 3c298f89-4303-0410-b956-a3cf2f4a3e73