clk: qcom: clk-cpu-osm: remove CPR revision check from MX supply voting

Remove the CPR fusing revision check from the logic which
determines if a given frequency requires the MX supply at
Nominal or Turbo voltage level.  This is needed as some later
revision parts may require MX at Turbo for high frequencies.

Also, make MX supply voting optional.

Change-Id: I5c5ac1aaa756197e68f5077ff8baaf94e513aab7
Signed-off-by: David Collins <collinsd@codeaurora.org>