tx493xide: use min_t() macro instead of min()

This fixes a warning ("comparison of distinct pointer types lacks a
cast") introduced by the commit
040f6b4f14adb2ca5babb84e9fb2ebc6661e0be2 ("tx493xide: use ->pio_mode
value to determine pair device speed").

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/ide/tx4938ide.c b/drivers/ide/tx4938ide.c
index 1d80f1f..7002765 100644
--- a/drivers/ide/tx4938ide.c
+++ b/drivers/ide/tx4938ide.c
@@ -64,7 +64,7 @@
 
 	pair = ide_get_pair_dev(drive);
 	if (pair)
-		safe = min(safe, pair->pio_mode - XFER_PIO_0);
+		safe = min_t(u8, safe, pair->pio_mode - XFER_PIO_0);
 	tx4938ide_tune_ebusc(pdata->ebus_ch, pdata->gbus_clock, safe);
 }