libata: use ata_tag_internal() consistently

Some check for the value directly, use the provided helper instead.
Also make it return a bool, since that's what it does.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 28e1af2..143cdad 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -5120,7 +5120,7 @@ int ata_sas_allocate_tag(struct ata_port *ap)
 		tag = tag < max_queue ? tag : 0;
 
 		/* the last tag is reserved for internal command. */
-		if (tag == ATA_TAG_INTERNAL)
+		if (ata_tag_internal(tag))
 			continue;
 
 		if (!test_and_set_bit(tag, &ap->sas_tag_allocated)) {