configs: e850-96: Enable USB host support

Exynos850 SoC has a dual-role USB controller which can be configured in
USB host role. As it's the only one USB controller on the board, it's
shared between "device" USB connector (micro-USB) and host USB
connectors. The hardware automatically powers on the host related parts
when the micro-USB cable (for device role) is being disconnected. Also,
as U-Boot lacks dynamic USB role switching capability, the only way to
switch the role at the moment is to modify "dr_mode" property in
U-Boot's device tree file here:

    dts/upstream/src/arm64/exynos/exynos850-e850-96.dts

This won't affect the dynamic role switching later in Linux kernel, as a
separate (different) device tree blob is provided to the kernel.

Enable the USB host support and corresponding commands to make it
functional in E850-96 board.

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>

configs/e850-96_defconfig

@@ -29,6 +29,8 @@ CONFIG_CMD_CLK=y
 CONFIG_CMD_DFU=y
 CONFIG_CMD_GPT=y
 CONFIG_CMD_MMC=y
+CONFIG_CMD_USB=y
+CONFIG_CMD_USB_MASS_STORAGE=y
 CONFIG_CMD_EFIDEBUG=y
 # CONFIG_CMD_DATE is not set
 CONFIG_CMD_RTC=y
@@ -63,6 +65,9 @@ CONFIG_SYSRESET=y
 CONFIG_SYSRESET_SYSCON=y
 CONFIG_USB=y
 CONFIG_DM_USB_GADGET=y
+CONFIG_USB_XHCI_HCD=y
+CONFIG_USB_XHCI_DWC3=y
+CONFIG_USB_XHCI_DWC3_OF_SIMPLE=y
 CONFIG_USB_DWC3=y
 CONFIG_USB_DWC3_GENERIC=y
 CONFIG_USB_GADGET=y