net: dwc_eth_qos: add support for sun55i platform
The Allwinner sun55i (A523/A527/T527) platform features the Synopsys
DesignWare Ethernet QOS IP. To enable this GMAC controller in U-Boot,
this introduces the glue layer responsible for configuring the
corresponding clocks, resets, and syscon registers.
This implementation is directly ported from upstream Linux kernel commit
f603808a98af ("net: stmmac: Add support for Allwinner A523 GMAC200").
Link: https://patch.msgid.link/20250925191600.3306595-3-wens@kernel.org
Signed-off-by: Junhui Liu <junhui.liu@pigmoral.tech>