tests: Properly pass the num of channels to start.sh

The number of channels was not properly passed from the
run-all.sh script to the start.sh script. Fix it.

Signed-off-by: Ilan Peer <ilan.peer@intel.com>

tests/hwsim/run-all.sh

@@ -108,7 +108,7 @@ if [ ! -z "$BUILD" ]; then
     fi
 fi
 
-if ! ./start.sh $VALGRIND $TRACE $NUM_CH; then
+if ! ./start.sh $VALGRIND $TRACE channels=$NUM_CH; then
 	if ! [ -z "$LOGBASEDIR" ] ; then
 		echo "Could not start test environment" > $LOGDIR/run
 	fi