prevent out-of-bounds access with SCSI_IOCTL_GET_PCI
disk_info_from_fd(): group output parameters into struct disk_info
produce virtio-blk device paths under EDD 3.0
produce virtio-scsi device paths under EDD 3.0
disk_get_virt_pci(): generalize to arbitrary major & minor device numbers
disk_get_pci(): expose detected interface type
disk_info_from_fd(): get major/minor from buf.st_rdev
Fix unchecked malloc calls.