arm64: dts: qcom: apq8016-sbc: Add overlay for usb host mode

Due to the presence of the fastboot micro cable in the CI farm,
it causes the hardware to remain in gadget mode instead of host mode.
So it doesn't find the network, which results in failure to mount root
fs via NFS.

Add an overlay dtso file that sets the dr_mode to host, allowing the
USB controllers to work in host mode. With commit 15d16d6d
("kbuild: Add generic rule to apply fdtoverlay"), overlay target can
be used to simplify the build of DTB overlays. It uses fdtoverlay to
merge base device tree with the overlay dtso. apq8016-sbc-usb-host.dtb
file can be used by drm-ci, mesa-ci.
Suggested-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Suggested-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Helen Koike <helen.koike@collabora.com>
Signed-off-by: David Heidelberg <david.heidelberg@collabora.com>
Signed-off-by: Vignesh Raman <vignesh.raman@collabora.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Acked-by: Helen Koike <helen.koike@collabora.com>
Link: https://lore.kernel.org/r/20230911161518.650726-1-vignesh.raman@collabora.comSigned-off-by: Bjorn Andersson <andersson@kernel.org>

arch/arm64/boot/dts/qcom/Makefile

 # SPDX-License-Identifier: GPL-2.0
 dtb-$(CONFIG_ARCH_QCOM)	+= apq8016-sbc.dtb
+
+apq8016-sbc-usb-host-dtbs	:= apq8016-sbc.dtb apq8016-sbc-usb-host.dtbo
+
+dtb-$(CONFIG_ARCH_QCOM)	+= apq8016-sbc-usb-host.dtb
 dtb-$(CONFIG_ARCH_QCOM)	+= apq8016-sbc-d3-camera-mezzanine.dtb
 dtb-$(CONFIG_ARCH_QCOM)	+= apq8039-t2.dtb
 dtb-$(CONFIG_ARCH_QCOM)	+= apq8094-sony-xperia-kitakami-karin_windy.dtb

arch/arm64/boot/dts/qcom/apq8016-sbc-usb-host.dtso

+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+
+/dts-v1/;
+/plugin/;
+
+&usb {
+         dr_mode = "host";
+};