staging: dgnc: Remove unneeded dgnc_trace.c and dgnc_trace.h

Removes unneeded dgnc_trace.c and dgnc_trace.h

CC: Lidza Louina <lidza.louina@gmail.com>
CC: Mark Hounschell <markh@compro.net>
Signed-off-by: Seunghun Lee <waydi1@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>