ata: libata-scsi: Fix ata_mselect_control_ata_feature() return type

The function ata_mselect_control_ata_feature() has a return type defined
as unsigned int but this function may return negative error codes, which
are correctly propagated up the call chain as integers.

Fix ata_mselect_control_ata_feature() to have the correct int return
type.

While at it, also fix a typo in this function description comment.

Fixes: df60f9c6 ("scsi: ata: libata: Add ATA feature control sub-page translation")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Reviewed-by: Igor Pylypiv <ipylypiv@google.com>