phy: qualcomm: phy-qcom-eusb2-repeater: Zero out untouched tuning regs

The vendor kernel zeroes out all tuning data outside the init sequence
as part of initialization. Follow suit to avoid UB.

Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20230830-topic-eusb2_override-v2-3-7d8c893d93f6@linaro.org


Signed-off-by: Vinod Koul <vkoul@kernel.org>