drm/msm/dsi-staging: add vote for ldo1 from dsi phy

DSI PLL is powered by 0p9 supply,this change fixes bug where
dsi was missing its vote on 0p9 regulator.

Change-Id: I44ba5baa8c352cf92e5f4c9239dba81d2c3dd8c0
Signed-off-by: Vara Reddy <varar@codeaurora.org>