Revert "ARM: dts: msm: update default mdp clock for 120 fps on kona target"

460Mhz clk_set_rate request from sde driver is failing in clk
driver sometimes during bootup. This reverts commit b1427106
("ARM: dts: msm: update default mdp clock for 120 fps on kona target")
until fix from clock driver is root caused and merged.

Change-Id: I8aa911951db6c45c72cfa88a814755dfd1330fa8