clk: qcom: Update logic to get the cpu node

Current logic to get the cpu node works fine with cpu reg
property with address-cells equal to 1 but for latest
kernel version, address-cells could be 1 or 2 depending upon
the MPIDR_EL1 register size. So add support for the same by
updating the logic to get cpu node value.

Change-Id: I23413e7b148f636bd72aa8c1a15a1aec3c52b9c5
Signed-off-by: Amit Nischal <anischal@codeaurora.org>