qemu arm no longer able to boot RPI Kernels

Since RPi Kernel 1.20170427, qemu is no longer able to emulate the Rasberry Pi, as the linux kernel is complaining about timing issues.

Old kernel output - https://pastebin.com/wvkneNNF
New kernel output - https://pastebin.com/QTwgCkV2

Note that the actual error is caused by the kernel being unable to get the timing source for the mmc (Line 160), which causes an unable-to-mount-root panic.  There are other issues with the serial port returning an invalid speed, which displays a divide-by-zero error, which is PROBABLY a symptom of the same root cause.

This is simple to replicate - The last working kernel is available here:

https://github.com/raspberrypi/firmware/tree/1.20170405/boot

Download kernel7 and the dtb, and try to boot with (for example)

qemu-system-aarch64 -M raspi2 -kernel kernel7.img -dtb bcm2709-rpi-2-b.dtb -serial stdio -sd noobs.img -append "root=/dev/mmcblk0p2 init=/bin/bash"

This works, and boots successfully.   

However, if you replace the kernel7.img and dtb with ones taken from https://github.com/raspberrypi/firmware/tree/1.20170427/boot it will NOT boot because of various clock timing issues (as in the second paste)