libata: make the function name in comment match the actual function

The function name used to be ata_scsiop_mode_select() but renamed to
ata_scsi_mode_select_xlat().  Update the comment accordingly.

tj: Minor commit desc update.

Signed-off-by: Minwoo Im <dn3108@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>