These functions are not called for any location.
This patch removes them scsi_trim_trail(), scsi_get_disk_count()
and scsi_setup_read6().

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>