The deprecation message (see previous patch) was about the
"ppc ``ref405ep`` machine". Is that OK we remove these CPUs
for user emulation?
$ qemu-ppc -cpu help|fgrep 405
PowerPC 405d2 PVR 20010000
PowerPC 405gpa PVR 40110000
PowerPC 405gpb PVR 40110040
PowerPC 405cra PVR 40110041
PowerPC 405gpc PVR 40110082
PowerPC 405gpd PVR 401100c4
PowerPC 405gp (alias for 405gpd)
PowerPC 405crb PVR 401100c5
PowerPC 405crc PVR 40110145
PowerPC 405cr (alias for 405crc)
PowerPC 405gpe (alias for 405crc)
PowerPC npe405h PVR 414100c0
PowerPC npe405h2 PVR 41410140
PowerPC 405ez PVR 41511460
PowerPC npe405l PVR 416100c0
PowerPC 405d4 PVR 41810000
PowerPC 405 (alias for 405d4)
PowerPC 405lp PVR 41f10000
PowerPC 405gpr PVR 50910951
PowerPC 405ep PVR 51210950