firmware: arm_scmi: Clear stale xfer->hdr.status

Stale error status reported from a previous message transaction must be
cleared before starting a new transaction to avoid being confusingly
reported in the following SCMI message dump traces.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20221222183823.518856-2-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

drivers/firmware/arm_scmi/driver.c

@@ -910,6 +910,8 @@ static int do_xfer(const struct scmi_protocol_handle *ph,
 			      xfer->hdr.protocol_id, xfer->hdr.seq,
 			      xfer->hdr.poll_completion);
 
+	/* Clear any stale status */
+	xfer->hdr.status = SCMI_SUCCESS;
 	xfer->state = SCMI_XFER_SENT_OK;
 	/*
 	 * Even though spinlocking is not needed here since no race is possible