ata: sata_dwc_460ex: Remove unused forward declaration

sata_dwc_port_stop() is not used before being defined,
remove redundant forward declaration.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>

drivers/ata/sata_dwc_460ex.c

@@ -185,7 +185,6 @@ static void sata_dwc_bmdma_start_by_tag(struct ata_queued_cmd *qc, u8 tag);
 static int sata_dwc_qc_complete(struct ata_port *ap, struct ata_queued_cmd *qc,
 				u32 check_status);
 static void sata_dwc_dma_xfer_complete(struct ata_port *ap, u32 check_status);
-static void sata_dwc_port_stop(struct ata_port *ap);
 static void sata_dwc_clear_dmacr(struct sata_dwc_device_port *hsdevp, u8 tag);
 
 #ifdef CONFIG_SATA_DWC_OLD_DMA