net: stmmac: Fix E2E delay mechanism

When utilizing End to End delay mechanism, the following error messages show up:

|root@ehl1:~# ptp4l --tx_timestamp_timeout=50 -H -i eno2 -E -m
|ptp4l[950.573]: selected /dev/ptp3 as PTP clock
|ptp4l[950.586]: port 1: INITIALIZING to LISTENING on INIT_COMPLETE
|ptp4l[950.586]: port 0: INITIALIZING to LISTENING on INIT_COMPLETE
|ptp4l[952.879]: port 1: new foreign master 001395.fffe.4897b4-1
|ptp4l[956.879]: selected best master clock 001395.fffe.4897b4
|ptp4l[956.879]: port 1: assuming the grand master role
|ptp4l[956.879]: port 1: LISTENING to GRAND_MASTER on RS_GRAND_MASTER
|ptp4l[962.017]: port 1: received DELAY_REQ without timestamp
|ptp4l[962.273]: port 1: received DELAY_REQ without timestamp
|ptp4l[963.090]: port 1: received DELAY_REQ without timestamp

Commit f2fb6b62 ("net: stmmac: enable timestamp snapshot for required PTP
packets in dwmac v5.10a") already addresses this problem for the dwmac
v5.10. However, same holds true for all dwmacs above version v4.10. Correct the
check accordingly. Afterwards everything works as expected.

Tested on Intel Atom(R) x6414RE Processor.

Fixes: 14f34733 ("net: stmmac: Correctly take timestamp for PTPv2")
Fixes: f2fb6b62

 ("net: stmmac: enable timestamp snapshot for required PTP packets in dwmac v5.10a")
Suggested-by: Ong Boon Leong <boon.leong.ong@intel.com>
Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>