arm64: dts: qcom: sm6125-seine: Provide regulators to HS USB2 PHY

Document the use of l7, l10 and l15 in the High Speed Qualcomm USB2 PHY,
in order to keep the regulators voted on when USB is active.

Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221222203636.250190-3-marijn.suijten@somainline.org