libata-sff: separate out BMDMA qc_issue

Separate out ata_bmdma_qc_issue() from ata_sff_qc_issue() such that
ata_sff_qc_issue() only deals with non-BMDMA SFF protocols (PIO and
nodata) while ata_bmdma_qc_issue() deals with the BMDMA protocols and
uses ata_sff_qc_issue() for non-DMA commands.  All the users are
updated accordingly.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/include/linux/libata.h b/include/linux/libata.h
index d973972..ee84e7e 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -1626,6 +1626,7 @@
 #endif /* CONFIG_PCI */
 
 extern void ata_bmdma_qc_prep(struct ata_queued_cmd *qc);
+extern unsigned int ata_bmdma_qc_issue(struct ata_queued_cmd *qc);
 extern void ata_bmdma_dumb_qc_prep(struct ata_queued_cmd *qc);
 extern void ata_bmdma_error_handler(struct ata_port *ap);
 extern void ata_bmdma_post_internal_cmd(struct ata_queued_cmd *qc);