msm: mdss: fix black screen issue during lk to kernel transition

While fixing device boot issue with video mode panel.
New logic was added to prevent the clock turn off for video mode
panel. Which updated the return value of mdp3_is_display_on and
mdp3_panel_get_intf_status function and resulted on black screen
issue on command mode because splash status was not reflected
correctly in the driver.
Fix the issue by avoiding return value update in above
function calls.

Change-Id: Ia255712dad083ec17b863d1ae7875ce04cf4aae5
Signed-off-by: Sachin Bhayare <sachin.bhayare@codeaurora.org>