cpukit/dev/can: correct round-robin on same priority Tx

When the device is open multiple times and data
are sent to driver by multiple FIFOs/edges then
round-robin between same priority prevents
one application blocking whole bandwidth.

The problem has been introduced during switch
from original uLUt/LinCAN to NewLib provided TAILQ

Signed-off-by: Pavel Pisa <ppisa@pikron.com>

cpukit/dev/can/can-queue.c

@@ -391,7 +391,7 @@ int rtems_can_queue_test_outslot(
             TAILQ_REMOVE( edge->peershead, edge, activepeers );
           }
           if ( out_ready ) {
-            TAILQ_INSERT_HEAD(
+            TAILQ_INSERT_TAIL(
               &qends->active[ edge->edge_prio ],
               edge,
               activepeers

cpukit/include/dev/can/can-impl.h

@@ -535,7 +535,7 @@ static inline void rtems_can_queue_activate_edge(
         TAILQ_REMOVE( qedge->peershead, qedge, activepeers );
       }
 
-      TAILQ_INSERT_HEAD(
+      TAILQ_INSERT_TAIL(
         &output_ends->active[ qedge->edge_prio ],
         qedge,
         activepeers