kernel: Bump to 3.12.33

firmware: Avoid enabling 25MHz ethernet clock on model A+
See: http://www.raspberrypi.org/forums/viewtopic.php?f=63&t=91267&start=25#p639575

firmware: Restructure of hdmi pll adjustment code. Add support for locking to 3:2 cadence (24fps on 60Hz)
firmware: video_render: Reduce processing time to avoid dropouts with DTS audio
firmware: Add some upstream fixes for mmal and openmax

kernel: Initial test with trailing atom added to kernel.img
See: https://github.com/raspberrypi/tools/commit/774670ed53080f564ddb74879adcbd18d1730547
firmware: Revert upstream patch that breaks audio_render when used without clock
See: http://forum.kodi.tv/showthread.php?tid=192380&pid=1847655#pid1847655

firmware: venc: Release images when error after open occurs which prevents a hang.
See: https://github.com/raspberrypi/userland/issues/206
See: https://github.com/raspberrypi/firmware/issues/328
See: https://github.com/raspberrypi/firmware/issues/254
firmware: arm_loader: Adding support for device tree fragments/overlays
 This patch also tidies up the existing Hat overlay code.

firmware: Candidate patch to validate that the kernel supports DT blobs and automatically activate device tree
firmware: Fix for memory size being reported through device tree