hso: fix rx parsing logic when skb allocation fails

If skb allocation fails once the IP header has been received, the rx state is
being set to WAIT_SYNC. The logic, though, shouldn't directly return, as the
buffer may contain a full packet, and therefore the WAIT_SYNC state needs to be
processed (resetting state to WAIT_IP, clearing rx_buf_size and re-initializing
rx_buf_missing).

So, just let the while loop continue so that in the next iteration the WAIT_SYNC
state cleanly stops the loop. The WAIT_SYNC processing will be done just after
that, only if the end of packet is flagged.

Signed-off-by: Aleksander Morgado <aleksander@aleksander.es>
Signed-off-by: David S. Miller <davem@davemloft.net>