[1/4] Add kernel support for Sagemcom F@ST2704V2 ADSL router

This adds kernel support support for Sagemcom F@st 2704 wireless ADSL
router.
It's a BCM6328-based 802.11n wireless router with USB port and ADSL2+
modem equipped with 64 MiB RAM and 8 MiB flash.
[2/4] button-hotplug: Add KEY_RFKILL handling

This extends button-hotplug to allow userspace handlers for rfkill
events, enabling /etc/rc.button/rfkill script to work properly on
routers with rfkill switch.
[3/4] Add userspace support for Sagemcom F@ST2704V2 ADSL router

This adds userspace support for Sagemcom F@st 2704 router.
[4/4] Add profile and build image for Sagemcom F@ST2704V2 ADSL router

This adds profile and build image for Sagemcom F@st2704, using b43
driver. For WiFi to work properly BCMA fallback SPROM support patch must
be applied (see http://git.io/z1Ki8A).