mdss: dsi: Add first controller initialization in panel probe

For cont Splash feature for split display panels,
first controller has to be initialized in probe.
Move the first controller initialization from host init
to controller init function that is called during panel
probe.

Change-Id: Ib964877cd345adfc9f52e7ebe5dc59652a2de44e
Signed-off-by: Chandan Uddaraju <chandanu@codeaurora.org>