DT schema expects names of operating points tables to start with
"opp-table":

  ipq6018-cp01-c1.dtb: cpu_opp_table: $nodename:0: 'cpu_opp_table' does not match '^opp-table(-[a-z0-9]+)?$'

Use hyphens instead of underscores, fix the names to match DT schema or
remove the prefix entirely when it is not needed.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220627093250.84391-1-krzysztof.kozlowski@linaro.org