arm64: dts: sm8250-mtp: enable USB host nodes

Enable both USB host controller, hsphy and qmpphy nodes on sm8250. Add
missing pm8150 ldo18 definition (used by USB qmp phys). Both controllers
are locked to host mode: dual role on first controller is not enabled.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20201127092646.122663-1-dmitry.baryshkov@linaro.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>