rpi_0_w: Add configs consistent with RpI3

CONFIG_OF_EMBED in particular is needed to allow the Raspberry Pi
firmware to pass the DTB to U-Boot and on to the kernel.
Signed-off-by: NDrew Moseley <drew.moseley@northern.tech>

configs/rpi_0_w_defconfig

@@ -12,14 +12,21 @@ CONFIG_SYS_PROMPT="U-Boot> "
 CONFIG_CMD_GPIO=y
 CONFIG_CMD_MMC=y
 CONFIG_CMD_USB=y
+CONFIG_OF_EMBED=y
+CONFIG_ENV_FAT_INTERFACE="mmc"
+CONFIG_ENV_FAT_DEVICE_AND_PART="0:1"
+CONFIG_DM_KEYBOARD=y
 CONFIG_DM_MMC=y
 CONFIG_MMC_SDHCI=y
 CONFIG_MMC_SDHCI_BCM2835=y
 CONFIG_DM_ETH=y
 CONFIG_USB=y
 CONFIG_DM_USB=y
+CONFIG_USB_DWC2=y
 CONFIG_USB_STORAGE=y
 CONFIG_USB_KEYBOARD=y
+CONFIG_USB_HOST_ETHER=y
+CONFIG_USB_ETHER_SMSC95XX=y
 CONFIG_DM_VIDEO=y
 CONFIG_SYS_WHITE_ON_BLACK=y
 CONFIG_CONSOLE_SCROLL_LINES=10