[PATCH] libata: fix ata_xfer_tbl termination

ata_xfer_tbl is terminated by entry with -1 as ->shift.  However,
->shift was unsigned int making the termination condition bogus.  This
patch converts ->shift and ->bits to int.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

drivers/scsi/libata-core.c

@@ -278,7 +278,7 @@ static void ata_unpack_xfermask(unsigned int xfer_mask,
 }
 
 static const struct ata_xfer_ent {
-	unsigned int shift, bits;
+	int shift, bits;
 	u8 base;
 } ata_xfer_tbl[] = {
 	{ ATA_SHIFT_PIO, ATA_BITS_PIO, XFER_PIO_0 },