Refactor to eliminate warning in 13 tools.

  The ethernet_tx_server code performed a transaction on an array member.
  In the 13 tools this will warn unless the array member is only accessed
  one in the first statement of the transaction. This is fixed by
  outlining the code to a transaction function.

(cherry picked from commit 2853e1607bb287d73f9c96a4265921dc28917a68)

Conflicts:
	module_ethernet/src/full/ethernet_tx_server.xc