firmware: arm_scmi: Perform earlier cinfo lookup call in do_xfer

Lookup cinfo data early in do_xfer so as to avoid any further init work
on xfer structure in case of error.

No functional change.

Link: https://lore.kernel.org/r/20211129191156.29322-2-cristian.marussi@arm.comReviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NCristian Marussi <cristian.marussi@arm.com>
Signed-off-by: NSudeep Holla <sudeep.holla@arm.com>

drivers/firmware/arm_scmi/driver.c

@@ -766,6 +766,10 @@ static int do_xfer(const struct scmi_protocol_handle *ph,
 		return -EINVAL;
 	}
 
+	cinfo = idr_find(&info->tx_idr, pi->proto->id);
+	if (unlikely(!cinfo))
+		return -EINVAL;
+
 	/*
 	 * Initialise protocol id now from protocol handle to avoid it being
 	 * overridden by mistake (or malice) by the protocol code mangling with
@@ -774,10 +778,6 @@ static int do_xfer(const struct scmi_protocol_handle *ph,
 	xfer->hdr.protocol_id = pi->proto->id;
 	reinit_completion(&xfer->done);
 
-	cinfo = idr_find(&info->tx_idr, xfer->hdr.protocol_id);
-	if (unlikely(!cinfo))
-		return -EINVAL;
-
 	trace_scmi_xfer_begin(xfer->transfer_id, xfer->hdr.id,
 			      xfer->hdr.protocol_id, xfer->hdr.seq,
 			      xfer->hdr.poll_completion);