irqchip/gic-v3-its: Zero command on allocation

When reusing commands from the ring buffer, it would be better
to zero them out, even if the ITS should ignore the unused
fields.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index ee928de..4a895c6 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -411,6 +411,12 @@
 	if (its->cmd_write == (its->cmd_base + ITS_CMD_QUEUE_NR_ENTRIES))
 		its->cmd_write = its->cmd_base;
 
+	/* Clear command  */
+	cmd->raw_cmd[0] = 0;
+	cmd->raw_cmd[1] = 0;
+	cmd->raw_cmd[2] = 0;
+	cmd->raw_cmd[3] = 0;
+
 	return cmd;
 }