km/kirkwood: enable USB support and the host controller driver

Our kirkwood device embeds a USB host controller that is now used
on some boards. This enables the support of USB and the corresponding
driver.

Signed-off-by: Holger Brunck <holger.brunck@hitachi-powergrids.com>
CC: Stefan Roese <sr@denx.de>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/board/keymile/km_arm/Kconfig b/board/keymile/km_arm/Kconfig
index 4b21db8..6f55cfa 100644
--- a/board/keymile/km_arm/Kconfig
+++ b/board/keymile/km_arm/Kconfig
@@ -58,8 +58,12 @@
 	select DM_SERIAL
 	select DM_SPI
 	select DM_SPI_FLASH
+	select USB
+	select USB_EHCI_HCD
+	select USB_EHCI_MARVELL
 	imply CMD_CRAMFS
 	imply CMD_DIAG
 	imply FS_CRAMFS
+	imply CMD_USB
 
 endif