optee: fix invalid of_node_put() in optee_driver_init()

The first node supplied to of_find_matching_node() has its reference
counter decreased as part of call to that function. In optee_driver_init()
after calling of_find_matching_node() it's invalid to call of_node_put() on
the supplied node again.

So remove the invalid call to of_node_put().

Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
diff --git a/drivers/tee/optee/core.c b/drivers/tee/optee/core.c
index 58169e5..18c8c0a 100644
--- a/drivers/tee/optee/core.c
+++ b/drivers/tee/optee/core.c
@@ -589,7 +589,6 @@
 		return -ENODEV;
 
 	np = of_find_matching_node(fw_np, optee_match);
-	of_node_put(fw_np);
 	if (!np)
 		return -ENODEV;