Kernel prepatch 5.3-rc2

The 5.3-rc2 kernel prepatch is availablefor testing. "There are fixes all over, I don't think there's much of a patternhere. The three areas that do stand out are Documentation (more rstconversions), arch updates (mainly because of the netx arm platformremoval) and misc driver fixes (gpu, iommu, net, nvdimm, sound..)".