arm64: dts: qcom: ipq9574: Add CMN PLL node

arm64: dts: qcom: ipq9574: Add CMN PLL node

The CMN PLL clock controller allows selection of an input clock rate
from a defined set of input clock rates. It in-turn supplies fixed
rate output clocks to the hardware blocks that provide the ethernet
functions such as PPE (Packet Process Engine) and connected switch or
PHY, and to GCC.

The reference clock of CMN PLL is routed from XO to the CMN PLL through
the internal WiFi block.
.XO (48 MHZ or 96 MHZ)-->WiFi (multiplier/divider)-->48 MHZ to CMN PLL.

The reference input clock from WiFi to CMN PLL is fully controlled by
the bootstrap pins which select the XO frequency (48 MHZ or 96 MHZ).
Based on this frequency, the divider in the internal Wi-Fi block is
automatically configured by hardware (1 for 48 MHZ, 2 for 96 MHZ), to
ensure output clock to CMN PLL is 48 MHZ.

Signed-off-by: Luo Jie <quic_luoj@quicinc.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250103-qcom_ipq_cmnpll-v8-4-c89fb4d4849d@quicinc.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>