arm: kirkwood: nsa310s: Use Marvell uclass mvgbe and PHY driver for DM Ethernet

arm: kirkwood: nsa310s: Use Marvell uclass mvgbe and PHY driver for DM Ethernet

The Zyxel NSA310s board has the network chip Marvell Alaska 88E1318S.
Use uclass mvgbe and the compatible driver M88E1310 driver to bring
up Ethernet.

- Use uclass mvgbe to bring up the network. And remove ad-hoc code.
- Remove CONFIG_RESET_PHY_R.
- Enable CONFIG_PHY_MARVELL to properly configure the network.
- Add phy mode RGMII to kirkwood-nsa310s.dts
- Miscellaneous changes: Move constants to .c file and remove header file
board/zyxel/nsa310s/nsa310s.h, add support for large USB and SATA HDDs,
use BIT macro, add/cleanup comments, and cosmetic changes.

Note that this patch is depended on the following patch:
https://patchwork.ozlabs.org/project/uboot/patch/20220412201820.10291-1-mibodhi@gmail.com/

Signed-off-by: Tony Dinh <mibodhi@gmail.com>