ARM: dts: msm: move devfreq nodes inside soc node for sm6150

Multiple cpu_bw_mon nodes are listed under root dt node
which is incorrect. Fix this by moving them under soc node
for sm6150 target.

Change-Id: I37b15ca37355fb16ec9d6908cc64c4e1acfb8c10
Signed-off-by: Santosh Mardi <gsantosh@codeaurora.org>