`ot_earlgrey`: add ePMP configuration machine property with facade feature#241

jwnrt wants to merge 2 commits intolowRISC:ot-9.2.0lowRISC/qemu:ot-9.2.0from

jwnrt:jw/pmp-facadejwnrt/qemu:jw/pmp-facadeCopy head branch name to clipboard