mailbox: Rename free() to rfree()

This function name conflicts with our desire to #define free() to
something else on sandbox. Since it deals with resources, rename it to
rfree().

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/mailbox/k3-sec-proxy.c b/drivers/mailbox/k3-sec-proxy.c
index b07b56c..1194c6f 100644
--- a/drivers/mailbox/k3-sec-proxy.c
+++ b/drivers/mailbox/k3-sec-proxy.c
@@ -291,7 +291,7 @@
 struct mbox_ops k3_sec_proxy_mbox_ops = {
 	.of_xlate = k3_sec_proxy_of_xlate,
 	.request = k3_sec_proxy_request,
-	.free = k3_sec_proxy_free,
+	.rfree = k3_sec_proxy_free,
 	.send = k3_sec_proxy_send,
 	.recv = k3_sec_proxy_recv,
 };
diff --git a/drivers/mailbox/mailbox-uclass.c b/drivers/mailbox/mailbox-uclass.c
index 5968c9b..a6d2d1f 100644
--- a/drivers/mailbox/mailbox-uclass.c
+++ b/drivers/mailbox/mailbox-uclass.c
@@ -105,8 +105,8 @@
 
 	debug("%s(chan=%p)\n", __func__, chan);
 
-	if (ops->free)
-		return ops->free(chan);
+	if (ops->rfree)
+		return ops->rfree(chan);
 
 	return 0;
 }
diff --git a/drivers/mailbox/sandbox-mbox.c b/drivers/mailbox/sandbox-mbox.c
index bc917b3..442ca63 100644
--- a/drivers/mailbox/sandbox-mbox.c
+++ b/drivers/mailbox/sandbox-mbox.c
@@ -87,7 +87,7 @@
 
 struct mbox_ops sandbox_mbox_mbox_ops = {
 	.request = sandbox_mbox_request,
-	.free = sandbox_mbox_free,
+	.rfree = sandbox_mbox_free,
 	.send = sandbox_mbox_send,
 	.recv = sandbox_mbox_recv,
 };
diff --git a/drivers/mailbox/stm32-ipcc.c b/drivers/mailbox/stm32-ipcc.c
index c3df967..d4035a8 100644
--- a/drivers/mailbox/stm32-ipcc.c
+++ b/drivers/mailbox/stm32-ipcc.c
@@ -152,7 +152,7 @@
 
 struct mbox_ops stm32_ipcc_mbox_ops = {
 	.request = stm32_ipcc_request,
-	.free = stm32_ipcc_free,
+	.rfree = stm32_ipcc_free,
 	.send = stm32_ipcc_send,
 	.recv = stm32_ipcc_recv,
 };
diff --git a/drivers/mailbox/tegra-hsp.c b/drivers/mailbox/tegra-hsp.c
index 9bee886..c463e6a 100644
--- a/drivers/mailbox/tegra-hsp.c
+++ b/drivers/mailbox/tegra-hsp.c
@@ -175,7 +175,7 @@
 struct mbox_ops tegra_hsp_mbox_ops = {
 	.of_xlate = tegra_hsp_of_xlate,
 	.request = tegra_hsp_request,
-	.free = tegra_hsp_free,
+	.rfree = tegra_hsp_free,
 	.send = tegra_hsp_send,
 	.recv = tegra_hsp_recv,
 };
diff --git a/include/mailbox-uclass.h b/include/mailbox-uclass.h
index e0618aa..3c60c76 100644
--- a/include/mailbox-uclass.h
+++ b/include/mailbox-uclass.h
@@ -49,14 +49,14 @@
 	 */
 	int (*request)(struct mbox_chan *chan);
 	/**
-	 * free - Free a previously requested channel.
+	 * rfree - Free a previously requested channel.
 	 *
 	 * This is the implementation of the client mbox_free() API.
 	 *
 	 * @chan:	The channel to free.
 	 * @return 0 if OK, or a negative error code.
 	 */
-	int (*free)(struct mbox_chan *chan);
+	int (*rfree)(struct mbox_chan *chan);
 	/**
 	* send - Send a message over a mailbox channel
 	*