ide: add IDE_HFLAG_RQSIZE_256 host flag

Add IDE_HFLAG_RQSIZE_256 host flag to tell ide_pci_setup_ports() to set
hwif->rqsize to 256 sectors.  Convert pdc202xx_old host driver to use it.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/include/linux/ide.h b/include/linux/ide.h
index ff9d293..c5b52dd 100644
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -1265,6 +1265,8 @@
 	IDE_HFLAG_LEGACY_IRQS		= (1 << 21),
 	/* force use of legacy IRQs */
 	IDE_HFLAG_FORCE_LEGACY_IRQS	= (1 << 22),
+	/* limit LBA48 requests to 256 sectors */
+	IDE_HFLAG_RQSIZE_256		= (1 << 23),
 };
 
 #ifdef CONFIG_BLK_DEV_OFFBOARD