mppa: pktio: fix return value of early send call. (Ref T710)
mppa: pktio: fix return value of early send call. (Ref T710)

Send requires the Rx side to be opened to work so it
 can send to the right DNoC tags.
If it is not the case, return 0 messages instead of an error

Signed-off-by: Nicolas Morey-Chaisemartin <7188b998d7bb37a035517aa285fa3f5a95344e80@kalray.eu>

kalray/odp-mppa,kalray/odp-mppa,kalray/odp-mppa,kalray/odp-mppa,kalray/odp-mppa,kalray/odp-mppa,kalray/odp-mppa