ARM: dts: msm: Use correct property name to pass values for sdm660

Use correct property name for passing voltage values for voting
core_ldo which is required for QMP PHY.

Change-Id: I042905f5971c653f580a6f4388555744ff3160cc
Signed-off-by: Vijayavardhan Vennapusa <vvreddy@codeaurora.org>