mach-tegra: tegra_mpdecision: remove scroff_single_core and add TODOs to screen on/off

Signed-off-by: Dennis Rassmann <showp1984@gmail.com>
mach-tegra: tegra_mpdecision: fix some last compile errors/warnings

Signed-off-by: Dennis Rassmann <showp1984@gmail.com>