fbdev: imxfb: add '*/' on a separate line in block comment

Linux kernel coding style uses '*/' on a separate line at the end of
multi line comments.

Fix block comments by moving '*/' at the end of block comments on a
separate line as reported by checkpatch:

WARNING: Block comments use a trailing */ on a separate line

Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Signed-off-by: Helge Deller <deller@gmx.de>