phy: qcom: m31-eusb2: Make USB repeater optional

phy: qcom: m31-eusb2: Make USB repeater optional

A repeater is not required for the PHY to function. On systems with
multiple PHY instances connected to a multi-port controller, some PHYs
may be unconnected. All PHYs must still probe successfully even without
attached repeaters, otherwise the controller probe fails.

So make it optional.

Signed-off-by: Wesley Cheng <wesley.cheng@oss.qualcomm.com>
[abel.vesa@oss.qualcomm.com: commit re-worded to reflect actual reason]
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: Bjorn Andersson <andersson@kernel.org>
Signed-off-by: Abel Vesa <abel.vesa@oss.qualcomm.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Link: https://patch.msgid.link/20260302-phy-qcom-m31-eusb2-make-repeater-optional-v2-1-dbf714c72056@oss.qualcomm.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>