ENGR00277792 video: mxsfb: Enable pan display function

ENGR00277792 video: mxsfb: Enable pan display function

- Add interrupt handle thread for vsync and frame done irq.
- Support MXCFB_WAIT_FOR_VSYNC call to get vsync signal
  in fb_ioctl function.
- Add flip_sem semaphore to check last frame done interrupt
  in pan display function.
- Add cur_blank variable to record current blank state.
- Move register_framebuffer function after lcdif controller
 enabled, struct of fb_info and lcdif controller should ready
 to work before register_framebuffer.

Signed-off-by: Sandor Yu <R01008@freescale.com>