msm: mdss: dsi: fix dsi init sequence with ulps during suspend feature

If continuous splash screen feature is disabled and ULPS during suspend
feature is enabled, DSI phy initialization does when device is booting
up, due to incorrect checks in the current implementation. Fix this issue
by ensuring that DSI phy initialization is always done when DSI interface
is turned on.

Signed-off-by: Aravind Venkateswaran <aravindh@codeaurora.org>
Change-Id: Icdc90eef8d5f3380b47f67268249eb670f8ca824