libata: Make ata_sg_clean() static again

Commit 70e6ad0c ("[PATCH] libata: prepare ata_sg_clean() for
invocation from EH") made ata_sg_clean() global, but no user outside
libata-core.c has ever materialized.
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NTejun Heo <tj@kernel.org>

drivers/ata/libata-core.c

@@ -4822,7 +4822,7 @@ static unsigned int ata_dev_init_params(struct ata_device *dev,
  *	LOCKING:
  *	spin_lock_irqsave(host lock)
  */
-void ata_sg_clean(struct ata_queued_cmd *qc)
+static void ata_sg_clean(struct ata_queued_cmd *qc)
 {
 	struct ata_port *ap = qc->ap;
 	struct scatterlist *sg = qc->sg;

drivers/ata/libata.h

@@ -89,7 +89,6 @@ extern int sata_down_spd_limit(struct ata_link *link, u32 spd_limit);
 extern int ata_down_xfermask_limit(struct ata_device *dev, unsigned int sel);
 extern unsigned int ata_dev_set_feature(struct ata_device *dev,
 					u8 enable, u8 feature);
-extern void ata_sg_clean(struct ata_queued_cmd *qc);
 extern void ata_qc_free(struct ata_queued_cmd *qc);
 extern void ata_qc_issue(struct ata_queued_cmd *qc);
 extern void __ata_qc_complete(struct ata_queued_cmd *qc);