arm64: dts: qcom: sdm670: add missing usb hstx nvmem cell

This nvmem cell is present on SDM670 as well as SDM845. Add it in SDM670
so there is proper tuning.

Signed-off-by: Richard Acayan <mailingradian@gmail.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221206231729.164453-3-mailingradian@gmail.com