arm: tegra kai:fix screen flicker when kernel boot up.

set vdd_pnl as 'boot_on' to avoid dropping panel VDD.
Bug 965398 959819

Signed-off-by: Linqiang Pu <dpu@nvidia.com>
Reviewed-on: http://git-master/r/95398
(cherry picked from commit 9f423c83e391fa8581de2c088b4dea8248da8ae1)

Change-Id: I513e004f7ec1a46c155825af9e6278c46ca444c5
Reviewed-on: http://git-master/r/96643
Reviewed-by: Rohan Somvanshi <rsomvanshi@nvidia.com>
Tested-by: Rohan Somvanshi <rsomvanshi@nvidia.com>