staging: sm750fb: fix block comments errors in ddk750_display.c

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

Signed-off-by: yeongjun Kim <iam.yeongjunkim@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>