bsg's SG_IO doesn't work on 32-bit userspace and 64-bit kernelspace.
The problem is that both sg and bsg drivers use SG_IO
ioctl. sg_ioctl_trans() does 32/64-bit conversion even against bsg
header. It messes up bsg header. bsg driver gets garbage.
This patch fixes sg_ioctl_trans to handle only sg header (struct
sg_io_hdr).