mdss_dsi_panel.c: add powersuspend hooks

Signed-off-by: Paul Reioux <reioux@gmail.com>
kernel/power/powersuspend: LCD screen on/off hooks (Yank555.lu)
- add an alternative hook for screen on / off detection in the display
  pannel driver
- sleeps  ~0.1s sooner, wakes up ~1s later then autosleep
- clean up source formatting a bit (Paul Reioux)

Signed-off-by: Paul Reioux <reioux@gmail.com>