Disable Ethernet in U-Boot if ODROID-M1 (#3122)

It seems that the Ethernet initialization in U-Boot causes significant
packet drops in Linux on some board. On a ODROID-M1 with 8GB of RAM, a
packet loss rate of ~20% has been observed. From the user point of view
it feels like a massive slow down (SSH feels very slow, Home Assistant
loads very slow or not at all).

Disabling the Ethernet controller driver avoids initialization in U-Boot
and makes Ethernet work correctly again in Linux.

While at it, drop the previously board specific configs. They haven't
been used and the board seemed fine without them.

buildroot-external/board/hardkernel/odroid-m1/uboot.config

@@ -1,5 +1,2 @@
-CONFIG_DOS_PARTITION=y
-# CONFIG_EFI_PARTITION is not set
-# CONFIG_USB_STORAGE is not set
-CONFIG_DISPLAY_BOARDINFO=y
-CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG=y
+# CONFIG_DWC_ETH_QOS is not set
+# CONFIG_DWC_ETH_QOS_ROCKCHIP is not set

buildroot-external/configs/odroid_m1_defconfig

@@ -137,7 +137,7 @@ BR2_TARGET_UBOOT_CUSTOM_GIT=y
 BR2_TARGET_UBOOT_CUSTOM_REPO_URL="https://github.com/u-boot/u-boot.git"
 BR2_TARGET_UBOOT_CUSTOM_REPO_VERSION="v2024.01"
 BR2_TARGET_UBOOT_BOARD_DEFCONFIG="odroid-m1-rk3568"
-BR2_TARGET_UBOOT_CONFIG_FRAGMENT_FILES="$(BR2_EXTERNAL_HASSOS_PATH)/bootloader/uboot.config"
+BR2_TARGET_UBOOT_CONFIG_FRAGMENT_FILES="$(BR2_EXTERNAL_HASSOS_PATH)/bootloader/uboot.config $(BR2_EXTERNAL_HASSOS_PATH)/board/hardkernel/odroid-m1/uboot.config"
 BR2_TARGET_UBOOT_NEEDS_PYLIBFDT=y
 BR2_TARGET_UBOOT_NEEDS_PYELFTOOLS=y
 BR2_TARGET_UBOOT_NEEDS_ATF_BL31=y