kernel: bump to 3.12.25

kernel: appletalk: Fix socket referencing in skb
See: https://github.com/raspberrypi/linux/issues/643

kernel: vcsm: VideoCore shared memory service for BCM2835
See: https://github.com/raspberrypi/linux/commit/1edb6ee324b08ede457082a91001ab911e026e40

kernel: Suppress harmless alsa warnings
See: https://github.com/raspberrypi/linux/issues/645

firmware: deinterlace: process yuvuv directly
See: http://openelec.tv/forum/124-raspberry-pi/71838-audio-cutting-out-when-deinterlace-is-on?start=15#113272

firmware: cec: Fix for reverting to incorrect state after a timeout

firmware: gpioman: Add default pulling to output pins
See: http://www.raspberrypi.org/forums/viewtopic.php?f=29&t=24682&start=25#p581749

firmware: ILCamera: Fix for AWB still being locked after a capture.
See: http://www.raspberrypi.org/forums/viewtopic.php?f=43&t=82021

firmware: OV5647: Add low frame rate (0.1666-1fps) 5MPix mode
See: http://www.raspberrypi.org/forums/viewtopic.php?f=43&t=82306&p=584070#p582537

firmware: Add MMAL parameter for privacy indicator control
See: https://github.com/raspberrypi/firmware/issues/186

firmware: camera: Add support for dual camera for CM from Serge

firmware: config: config: Add display_default_lcd option