video: fbdev: sm712fb.c: fix unaligned block comments warning

Fixed unaligned block comments warning generated by scripts/checkpatch.pl:
  WARNING: Block comments should align the * on each line

Signed-off-by: Lynn Lei <lynnl.wit@gmail.com>
Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Cc: Teddy Wang <teddy.wang@siliconmotion.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>