hw/pci-host/raven: Revert "raven: Move BIOS loading from board code to PCI host"

hw/pci-host/raven: Revert "raven: Move BIOS loading from board code to PCI host"

This reverts commit d0b25425749d5525b2ba6d9d966d8800a5643b35.

Loading firmware from the PCI host is unusual and raven is only used
by one board so this does not simplify anything but rather complicates
it. Revert to loading firmware from board code as that is the usual
way and also because raven has nothing to do with ROM so it is not a
good place for this.

Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <4ca4f71bf661923d9a91b7e6776a0e40726e2337.1746374076.git.balaton@eik.bme.hu>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>