ide: add IDE_HFLAG_LEGACY_IRQS host flag

Add IDE_HFLAG_LEGACY_IRQS host flag to tell ide_pci_setup_ports() to set
hwif->irq to legacy IRQ 14/15 (iff hwif->irq is not already set) and convert
atiixp, piix, serverworks, sis5513 and slc90e66 host drivers to use it.

While at it:

* In piix.c add IDE_HFLAGS_PIIX define and don't use ->init_hwif for MPIIX.

Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/pci/atiixp.c b/drivers/ide/pci/atiixp.c
index 18c181b..47e9580 100644
--- a/drivers/ide/pci/atiixp.c
+++ b/drivers/ide/pci/atiixp.c
@@ -172,9 +172,6 @@
 	u8 ch = hwif->channel;
 	struct pci_dev *pdev = hwif->pci_dev;
 
-	if (!hwif->irq)
-		hwif->irq = ch ? 15 : 14;
-
 	hwif->set_pio_mode = &atiixp_set_pio_mode;
 	hwif->set_dma_mode = &atiixp_set_dma_mode;
 	hwif->drives[0].autotune = 1;
@@ -200,7 +197,7 @@
 		.name		= "ATIIXP",
 		.init_hwif	= init_hwif_atiixp,
 		.enablebits	= {{0x48,0x01,0x00}, {0x48,0x08,0x00}},
-		.host_flags	= IDE_HFLAG_BOOTABLE,
+		.host_flags	= IDE_HFLAG_LEGACY_IRQS | IDE_HFLAG_BOOTABLE,
 		.pio_mask	= ATA_PIO4,
 		.mwdma_mask	= ATA_MWDMA2,
 		.udma_mask	= ATA_UDMA5,
@@ -208,7 +205,8 @@
 		.name		= "SB600_PATA",
 		.init_hwif	= init_hwif_atiixp,
 		.enablebits	= {{0x48,0x01,0x00}, {0x00,0x00,0x00}},
- 		.host_flags	= IDE_HFLAG_SINGLE | IDE_HFLAG_BOOTABLE,
+ 		.host_flags	= IDE_HFLAG_SINGLE | IDE_HFLAG_LEGACY_IRQS |
+				  IDE_HFLAG_BOOTABLE,
 		.pio_mask	= ATA_PIO4,
 		.mwdma_mask	= ATA_MWDMA2,
 		.udma_mask	= ATA_UDMA5,