Merge tag 'net-20250818' of https://source.denx.de/u-boot/custodians/u-boot-net

Pull request net-20250818.

This is mostly code cleanup and fixes, mainly for issues reported by the
Smatch tool, plus two small features for NET_LWIP as well as support for
the BCM54612E phy.

net-common:
- Fix a bunch of issues reported by Smatch
- Introduce CONFIG_DNS
- Add support for BCM54612E phy

net-legacy:
- Add missing SPDX-License-Identifier for files originating from LiMon

net-lwip:
- ping: initialize net_try_count to 1
- sntp: remove redundant sys_check_timeouts()
- tftp: resend initial request
- Add Kconfig option to show ICMP unreachable errors