clk: msm: 8937: Add support for spm pll management in msm8937

Make the corresponding device tree changes for SPM child node to probe.
This is required for the spm event management to be handled for the SR2/HF
PLL of C0/C1. Also accommodate latest frequency plan changes for debug mux
values to measure clock frequency.

Change-Id: Ia5d68331407a6ecdcf85e230ade7aa3fd497c466
Signed-off-by: Jaydeep Sen <jsen@codeaurora.org>