ARM: dts: msm: Disable shared display on DP display sa6155

Removed shared display configuration on DP interface as there
is no dynamic resolution detection for shared displays.

Change-Id: I5720eac361bec8ff32c6c03b64137a23aaacedd8
Acked-by: Poojashree Masthi <c_pmasth@qti.qualcomm.com>
Signed-off-by: Rahul Sharma <rahsha@codeaurora.org>