ide: fix serverworks.c UDMA regression

patch 0c824b51 in mainline.

The patch described by the following excerpt from ChangeLog-2.6.22 makes
it impossible to use UDMA on a Tyan S2707 motherboard (SvrWks CSB5):

commit 2d5eaa6d
Author: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Date:   Thu May 10 00:01:08 2007 +0200

    ide: rework the code for selecting the best DMA transfer mode (v3)

    ...

This one-line patch against 2.6.23 fixes the problem.
Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/ide/pci/serverworks.c

@@ -97,6 +97,7 @@ static u8 svwks_udma_filter(ide_drive_t *drive)
 			mode = 2;
 
 		switch(mode) {
+		case 3:	 mask = 0x3f; break;
 		case 2:	 mask = 0x1f; break;
 		case 1:	 mask = 0x07; break;
 		default: mask = 0x00; break;