[weekly][linaro] report week ending 8 Apr

Progress: * UM-2 [QEMU upstream maintainership] + Finished sorting out the exynos4210 SoC interrupt wiring and sent a patchset that cleans it up and makes it stop using qemu_split_irq() + rc3 tagged this week. We will need an rc4 next week for a couple of late-breaking security fixes.

* QEMU-420 [GICv4 emulation] + Finished the last bits of debugging and wiring up GICv4 support on the virt board, and sent initial patchset to the list for review: https://patchew.org/QEMU/20220408141550.1271295-1-peter.maydell@linaro.org/

-- PMM