Kconfig: USB: Migrate CONFIG_USB_EHCI_HCD users to Kconfig

Migrate the rest of the users of CONFIG_USB_EHCI_HCD over to Kconfig.
For a few SoCs, imply or default y this if USB is enabled.  In some
cases we had not already migrated to CONFIG_USB so do that as well.

Cc: Marek Vasut <marex@denx.de>
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Marek Vasut <marex@denx.de>
diff --git a/configs/MPC837XEMDS_HOST_defconfig b/configs/MPC837XEMDS_HOST_defconfig
index 774ecb8..787ac9d 100644
--- a/configs/MPC837XEMDS_HOST_defconfig
+++ b/configs/MPC837XEMDS_HOST_defconfig
@@ -17,5 +17,6 @@
 CONFIG_MTD_NOR_FLASH=y
 CONFIG_SYS_NS16550=y
 CONFIG_USB=y
+CONFIG_USB_EHCI_HCD=y
 CONFIG_USB_STORAGE=y
 CONFIG_OF_LIBFDT=y