ide: add IDE_HFLAG_SERIALIZE host flag

Add IDE_HFLAG_SERIALIZE host flag to tell ide_pci_setup_ports() to set
hwif/mate->serialized and convert aec62xx, cs5530 and sc1200 host drivers
to use it.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

include/linux/ide.h

@@ -1257,6 +1257,8 @@ enum {
 	IDE_HFLAG_NO_LBA48_DMA		= (1 << 18),
 	/* data FIFO is cleared by an error */
 	IDE_HFLAG_ERROR_STOPS_FIFO	= (1 << 19),
+	/* serialize ports */
+	IDE_HFLAG_SERIALIZE		= (1 << 20),
 };
 
 #ifdef CONFIG_BLK_DEV_OFFBOARD