ARM: dts: msm: config primary panel for msmsamarium

Configure the default primary panel used in msmsamarium
interposer cdp. Configure the PMIC GPIO for driving
DSI PWM. This change is needed for the default primary
panel to work on samarium interposer card.

Change-Id: I75270c564d99709ef53d4faaa14a3887d2609bc8
Signed-off-by: Manoj Rao <manojraj@codeaurora.org>