clk: qcom: qcs405: Always keep pcnoc usb2/3 clocks ON

The pcnoc USB2/3 clocks are connected to the PCNOC and turning them off
would result in NOC errors. So mark these clocks as critical and also
remove any parent relation so as to remove any voltage association with
these clocks.

Change-Id: I077444d07bd6900b195bb9a99672d3471a1f0464
Signed-off-by: Taniya Das <tdas@codeaurora.org>