net: tc: dont yield during net_rc tx/rx workq init

We init the net_tc tx/rx work queues during net_init() with a
call to init_rx_queues().  The L2/L3 and networking drivers have been
setup at this point.  If we yield the current thread, we risk
a call to net_recv_data() which calls net_queue_rx() which calls
net_tc_submit_to_rx_queue() on an RX work queue which hasn't been
setup yet.

This manifests as a boot hang under seemingly random circumstances.

Signed-off-by: Michael Scott <michael@opensourcefoundries.com>