configs: NVMe/USB target boot devices on VisionFive 2

Make NVMe and USB target boot devices on the StarFive VisionFive 2 board.
The boot devices are sorted by decreasing device speed.

CONFIG_PCI_INIT_R=y is set via [1]. 'start usb' is added to CONFIG_PREBOOT
by the same patch.

[1] [PATCH v1 1/2] configs: starfive: Enable PCIE auto enum and NVME/USB stuff for Starfive Visionfive 2
    https://lore.kernel.org/u-boot/TY3P286MB2611C9AD6E5BB3756A959E89981FA@TY3P286MB2611.JPNP286.PROD.OUTLOOK.COM/



Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>