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

Fixes an issue where DSI was missing its vote
on the 0p9 regulator required for the DSI PLL.

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