of/irq: add missing of_node_put

for_each_matching_node performs an of_node_get on each iteration, so
a break out of the loop requires an of_node_put.

A simplified version of the semantic patch that fixes this problem is as
follows (http://coccinelle.lip6.fr

):

// <smpl>
@@
local idexpression n;
expression e;
identifier l;
@@

 for_each_matching_node(n,...) {
   ...
(
   of_node_put(n);
|
   e = n
|
+  of_node_put(n);
?  goto l;
)
   ...
 }
...
l: ... when != n
// </smpl>

Besides the issue found by the semantic patch, this code also stores the
device_node value in a list, which requires an of_node_get, and then cleans
up the list on exit from the function, which requires an of_node_put.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Rob Herring <robh@kernel.org>