added GW5400-B/GW5410 support

- updated Gateworks kernel patch/config
- replaced recipe overried with bbappends
added support for GW5400-b and GW5410

    - added gpmi-nand support and use for env
    - added ubi/ubifs support
    - gpio assignments and pin-mux per-board
    - store eeprom config in global and read once
    - spin until we can access eeprom
    - wrap GSC i2c access with retries around NAK's
    - added gsc command to show hwmon
    - added phy LED config for eth0
    - use hwconfig for msata/rs232/gpio config
    - add GSC watchdog timer disable
    - cleanup devicetree fixups (rely on alises)
    - break out clock/ddr/sdram config into ventana-specific files