interconnect: qcom: rpm: Don't use clk_get_optional for bus clocks anymore

Commit dd42ec8e ("interconnect: qcom: rpm: Use _optional func for provider clocks")
relaxed the requirements around probing bus clocks. This was a decent
solution for making sure MSM8996 would still boot with old DTs, but
now that there's a proper fix in place that both old and new DTs
will be happy about, revert back to the safer variant of the
function.

Fixes: dd42ec8e ("interconnect: qcom: rpm: Use _optional func for provider clocks")
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20230228-topic-qos-v8-7-ee696a2c15a9@linaro.org


Signed-off-by: Georgi Djakov <djakov@kernel.org>