ide: add IDE_HFLAG_ABUSE_SET_DMA_MODE host flag

* Add IDE_HFLAG_ABUSE_SET_DMA_MODE host flag and use it to decide
  what to do with transfer modes < XFER_PIO_0 in ide_set_xfer_rate().

* Set IDE_HFLAG_ABUSE_SET_DMA_MODE in host drivers that need it
  (aec62xx, amd74xx, cs5520, cs5535, hpt34x, hpt366, pdc202xx_old,
  serverworks, tc86c001 and via82cxxx) and cleanup ->set_dma_mode
  methods in host drivers that don't (IDE core code guarantees that
  ->set_dma_mode will be called only for modes which are present
  in SWDMA/MWDMA/UDMA masks).

While at it:

* Add IDE_HFLAGS_HPT34X/HPT3XX/PDC202XX/SVWKS define in
  hpt34x/hpt366/pdc202xx_old/serverworks host driver.

There should be no functionality changes caused by this patch.

Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/pci/sis5513.c b/drivers/ide/pci/sis5513.c
index 3f35386..85d3699 100644
--- a/drivers/ide/pci/sis5513.c
+++ b/drivers/ide/pci/sis5513.c
@@ -351,25 +351,10 @@
 
 static void sis_set_dma_mode(ide_drive_t *drive, const u8 speed)
 {
-	/* Config chip for mode */
-	switch(speed) {
-		case XFER_UDMA_6:
-		case XFER_UDMA_5:
-		case XFER_UDMA_4:
-		case XFER_UDMA_3:
-		case XFER_UDMA_2:
-		case XFER_UDMA_1:
-		case XFER_UDMA_0:
-			sis_program_udma_timings(drive, speed);
-			break;
-		case XFER_MW_DMA_2:
-		case XFER_MW_DMA_1:
-		case XFER_MW_DMA_0:
-			sis_program_timings(drive, speed);
-			break;
-		default:
-			break;
-	}
+	if (speed >= XFER_UDMA_0)
+		sis_program_udma_timings(drive, speed);
+	else
+		sis_program_timings(drive, speed);
 }
 
 static u8 sis5513_ata133_udma_filter(ide_drive_t *drive)