ARM: dts: msm: Enable DP DM pulsing support on MSM8996

The charger associated with MSM8996 does not support
HVDCP detection by default. Enable DP DM pulsing support
so that charger driver can support HVDCP detection.
And all the 8996 platforms does not have this charger,
hence enable the pulsing support on those platforms
where this charger is present.

Change-Id: I70549df99bd11303d7c334227c869767f5ea51a8
Signed-off-by: Sriharsha Allenki <sallenki@codeaurora.org>