awg: Move MAC soft reset to awg_init_locked to avoid soft reset timeout

From NetBSD: Since the MAC can get stuck in reset state with no link, ignore
reset timeouts and continue with initializing the device.

Fixes "soft reset timeout" issue at boot with no network cable plugged in.

awg_init may be called multiple times throughout normal interface usage, so
the tx/rx descriptor base address registers must be written after each MAC
reset and are moved as such.

This problem has been observed on FreeBSD, H3/H2+ devices with an internal
PHY (includes OrangePi R1, OrangePi One at least).

Reviewed by: manu, ganbold
Obtained from: NetBSD
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D18844