powerpc: Starting machine ref405ep fails with "Could not load PowerPC BIOS 'ppc405_rom.bin'"

Not possible to start QEMU, see below. ppc405_rom.bin is missing from QEMU.

$ qemu-system-ppc -M ref405ep qemu-system-ppc: Could not load PowerPC BIOS 'ppc405_rom.bin'

QEMU emulator version 5.2.0

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information