net: stmmac: Add glue layer for Spacemit K3 SoC

net: stmmac: Add glue layer for Spacemit K3 SoC

The ethernet controller on Spacemit K3 SoC is Synopsys DesignWare
MAC (version 5.40a), with the following special points:
1. The rate of the tx clock line is auto changed when the mac speed
   rate is changed, and no need for changing the input tx clock.
2. This controller require a extra syscon device to configure the
   interface type, enable wake up interrupt and delay configuration
   if needed.

Add Spacemit dwmac driver support on the Spacemit K3 SoC.

Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/20260316010041.164360-4-inochiama@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>