clk: qcom: apss-ipq-pll: fix PLL rate for IPQ5018

According to ipq5018.dtsi, the maximum supported rate by the
CPU is 1.008 GHz on the IPQ5018 platform, however the current
configuration of the PLL results in 1.2 GHz rate.

Change the 'L' value in the PLL configuration to limit the
rate to 1.008 GHz. The downstream kernel also uses the same
value [1]. Also add a comment to indicate the desired
frequency.

[1] https://git.codelinaro.org/clo/qsdk/oss/kernel/linux-ipq-5.4/-/blob/NHSS.QSDK.12.4/drivers/clk/qcom/apss-ipq5018.c?ref_type=heads#L151

Fixes: 50492f92

 ("clk: qcom: apss-ipq-pll: add support for IPQ5018")
Signed-off-by: Gabor Juhos <j4g8y7@gmail.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20240326-fix-ipq5018-apss-pll-rate-v1-1-82ab31c9da7e@gmail.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>