ide: do not access ide_drive_t 'drive_data' field directly

Change ide_drive_t 'drive_data' field from 'unsigned int' type to 'void *'
type, allowing a wider range of values/types to be stored in this field.

Added 'ide_get_drivedata' and 'ide_set_drivedata' helpers to get and set
the 'drive_data' field.

Fixed all host drivers to maintain coherency with the change in the
'drive_data' field type.

Signed-off-by: Joao Ramos <joao.ramos@inov.pt>
[bart: fix qd65xx build, cast to 'unsigned long', minor Coding Style fixups]
Acked-by: Sergei Shtylyov <sshtylyov@ru.montavista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/opti621.c b/drivers/ide/opti621.c
index 6048eda..f1d70d6 100644
--- a/drivers/ide/opti621.c
+++ b/drivers/ide/opti621.c
@@ -138,6 +138,7 @@
 	ide_hwif_t *hwif = drive->hwif;
 	ide_drive_t *pair = ide_get_pair_dev(drive);
 	unsigned long flags;
+	unsigned long mode = XFER_PIO_0 + pio, pair_mode;
 	u8 tim, misc, addr_pio = pio, clk;
 
 	/* DRDY is default 2 (by OPTi Databook) */
@@ -150,11 +151,12 @@
 		{ 0x48, 0x34, 0x21, 0x10, 0x10 }	/* 25 MHz */
 	};
 
-	drive->drive_data = XFER_PIO_0 + pio;
+	ide_set_drivedata(drive, (void *)mode);
 
 	if (pair) {
-		if (pair->drive_data && pair->drive_data < drive->drive_data)
-			addr_pio = pair->drive_data - XFER_PIO_0;
+		pair_mode = (unsigned long)ide_get_drivedata(pair);
+		if (pair_mode && pair_mode < mode)
+			addr_pio = pair_mode - XFER_PIO_0;
 	}
 
 	spin_lock_irqsave(&opti621_lock, flags);