kernel: Added support to reserve/enable a GPIO pin to be used from pps-gpio module
See: https://github.com/raspberrypi/linux/pull/717

firmware: arm_loader: Add lock to rotated frame updates to avoid an unsafe update from mailbox channel
See: https://github.com/raspberrypi/firmware/issues/327

firmware: hdmi: Fix for attached flag in hdmi status when booting with cable disconnected
See: https://github.com/raspberrypi/firmware/issues/326