firmware: arm_scmi: Drop OF node reference in the transport channel setup

The OF node reference obtained from of_parse_phandle() should be dropped
if node is not compatible with arm,scmi-shmem.

Fixes: 507cd4d2 ("firmware: arm_scmi: Add compatibility checks for shmem node")
Cc: <stable@vger.kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20230719061652.8850-1-krzysztof.kozlowski@linaro.orgSigned-off-by: Sudeep Holla <sudeep.holla@arm.com>

drivers/firmware/arm_scmi/mailbox.c

@@ -166,8 +166,10 @@ static int mailbox_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
 		return -ENOMEM;
 
 	shmem = of_parse_phandle(cdev->of_node, "shmem", idx);
-	if (!of_device_is_compatible(shmem, "arm,scmi-shmem"))
+	if (!of_device_is_compatible(shmem, "arm,scmi-shmem")) {
+		of_node_put(shmem);
 		return -ENXIO;
+	}
 
 	ret = of_address_to_resource(shmem, 0, &res);
 	of_node_put(shmem);

drivers/firmware/arm_scmi/smc.c

@@ -137,8 +137,10 @@ static int smc_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
 		return -ENOMEM;
 
 	np = of_parse_phandle(cdev->of_node, "shmem", 0);
-	if (!of_device_is_compatible(np, "arm,scmi-shmem"))
+	if (!of_device_is_compatible(np, "arm,scmi-shmem")) {
+		of_node_put(np);
 		return -ENXIO;
+	}
 
 	ret = of_address_to_resource(np, 0, &res);
 	of_node_put(np);