net: ethernet: cs89x0: remove stale CONFIG_MACH_MX31ADS reference

[ Upstream commit 36a8d04a8293afcb9304cf0cd3741f67698f2a1a ]

The legacy ARM board file for MACH_MX31ADS was removed in commit
c93197b0041d ("ARM: imx: Remove i.MX31 board files"), but a reference
to it remained in the cs89x0 driver. Drop this unused code.

Signed-off-by: Ethan Nelson-Moore <enelsonmoore@gmail.com>
Fixes: c93197b0041d ("ARM: imx: Remove i.MX31 board files")
Link: https://patch.msgid.link/20260509023732.42256-1-enelsonmoore@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Ulrich Hecht <uli@kernel.org>

drivers/net/ethernet/cirrus/cs89x0.c

@@ -1270,7 +1270,6 @@ static const struct net_device_ops net_ops = {
 
 static void __init reset_chip(struct net_device *dev)
 {
-#if !defined(CONFIG_MACH_MX31ADS)
 	struct net_local *lp = netdev_priv(dev);
 	unsigned long reset_start_time;
 
@@ -1297,7 +1296,6 @@ static void __init reset_chip(struct net_device *dev)
 	while ((readreg(dev, PP_SelfST) & INIT_DONE) == 0 &&
 	       time_before(jiffies, reset_start_time + 2))
 		;
-#endif /* !CONFIG_MACH_MX31ADS */
 }
 
 /* This is the real probe routine.