rpmsg: glink: Propagate TX failures in intentless mode as well

rpmsg: glink: Propagate TX failures in intentless mode as well

As support for splitting transmission over several messages using
TX_DATA_CONT was introduced it does not immediately return the return
value of qcom_glink_tx().

The result is that in the intentless case (i.e. intent == NULL), the
code will continue to send all additional chunks. This is wasteful, and
it's possible that the send operation could incorrectly indicate
success, if the last chunk fits in the TX fifo.

Fix the condition.

Fixes: 8956927faed3 ("rpmsg: glink: Add TX_DATA_CONT command while sending")
Reviewed-by: Chris Lew <quic_clew@quicinc.com>
Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230418163018.785524-2-quic_bjorande@quicinc.com