arm: kirkwood: Dockstar : Add DM Ethernet

arm: kirkwood: Dockstar : Add DM Ethernet

The Dockstar board has the network chip Marvell 88E1116R. Convert to
Ethernet driver model, and use uclass mvgbe and the compatible driver
M88E1118R to bring up Ethernet.

- Add CONFIG_DM_ETH and associated configs.
- Add board_eth_init() to use uclass mvgbe to bring up the network.
And remove ad-hoc code.
- Add CONFIG_PHY_MARVELL to properly configure the network.
- Currently, CONFIG_RESET_PHY_R symbol is used in
arch/arm/mach-kirkwood/include/mach/config.h for all Kirkwood
boards with mv8831116 PHY, with each board defines the function
reset_phy(). Undefine it for this board.
- Miscellaneous changes: Move constants to .c file and remove
header file board/Seagate/dockstar/dockstar.h, use
CONFIG_SYS_THUMB_BUILD to keep u-boot image
under 512K, add CONFIG_HUSH_PARSER, use BIT macro, and cleanup comments.

- Note: This patch is a RESEND for a previous patch:
https://patchwork.ozlabs.org/project/uboot/patch/20210812051854.1340-2-mibodhi@gmail.com/

Signed-off-by: Tony Dinh <mibodhi@gmail.com>
Reviewed-by: Stefan Roese <sr@denx.de>