drm/msm/dsi: Update the "vdd" voltage range

The min and max voltage levels for the VDD input to DSI were initially set
to 2.85V (as suggested by the spec).

We have a platform (db410c) where the same regulator supply is also needed
by another consumer at a higher voltage. Bump up the max voltage level to
3.3V. No regressions are seen with this.

Signed-off-by: Archit Taneja <architt@codeaurora.org>