net: stmmac: convert to ndo_hwtstamp_get() and ndo_hwtstamp_set()

net: stmmac: convert to ndo_hwtstamp_get() and ndo_hwtstamp_set()

New timestamping API was introduced in commit 66f7223039c0 ("net: add
NDOs for configuring hardware timestamping") from kernel v6.6.

It is time to convert the stmmac driver to the new API, so that
timestamping configuration can be removed from the ndo_eth_ioctl()
path completely.

The existing timestamping calls are guarded by netif_running(). For
stmmac_hwtstamp_get() that is probably unnecessary, since no hardware
access is performed. But for stmmac_hwtstamp_set() I've preserved it,
since at least some IPs probably need pm_runtime_resume_and_get() to
access registers, which is otherwise called by __stmmac_open().

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Link: https://patch.msgid.link/20250514143249.1808377-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>