arch/powerpc/sysdev/qe_lib/qe.c: Add of_node_put to avoid memory leak

Add a call to of_node_put in the error handling code following a call to
of_find_compatible_node.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r exists@
local idexpression x;
expression E,E1;
statement S;
@@

*x =
(of_find_node_by_path
|of_find_node_by_name
|of_find_node_by_phandle
|of_get_parent
|of_get_next_parent
|of_get_next_child
|of_find_compatible_node
|of_match_node
)(...);
...
if (x == NULL) S
<... when != x = E
*if (...) {
  ... when != of_node_put(x)
      when != if (...) { ... of_node_put(x); ... }
(
  return <+...x...+>;
|
*  return ...;
)
}
...>
of_node_put(x);
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Acked-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

arch/powerpc/sysdev/qe_lib/qe.c

@@ -640,6 +640,7 @@ unsigned int qe_get_num_of_snums(void)
 		if ((num_of_snums < 28) || (num_of_snums > QE_NUM_OF_SNUM)) {
 			/* No QE ever has fewer than 28 SNUMs */
 			pr_err("QE: number of snum is invalid\n");
+			of_node_put(qe);
 			return -EINVAL;
 		}
 	}