staging: dgap: fixed "foo* bar should be foo * bar" in dgap.c

clean up checkpatch.pl error:
ERROR: "foo* bar" should be "foo *bar"

Signed-off-by: Daeseok Youn <daeseok.youn@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>