ARM: dts: msm: specify APM threshold voltage in OSM for msmcobalt

Define the APM threshold voltage to be used by the OSM device
to determine the correct APM supply selection for different
DCVS setpoints.

CRs-Fixed: 1021656 1030444
Change-Id: Iebeb45eaa2503bd5be19f00938d0dbec1163c5a5
Signed-off-by: Osvaldo Banuelos <osvaldob@codeaurora.org>