staging: dgnc: clean up dgnc_input function

This is for fixing checkpatch.pl warning about
"Alignment should match open parenthesis" but if that is
fixed, code line is over 80 characters.
I think "ch->ch_rqueue + tail + i" could be declared once in
the begining of loop.

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