arch/powerpc/sysdev/fsl_rmu.c: introduce missing kfree

rmu needs to be freed before leaving the function in an error case.

A simplified version of the semantic match that finds the problem is as
follows: (http://coccinelle.lip6.fr)

// <smpl>
@r exists@
local idexpression x;
statement S;
identifier f1;
position p1,p2;
expression *ptr != NULL;
@@

x@p1 = \(kmalloc\|kzalloc\|kcalloc\)(...);
...
if (x == NULL) S
<... when != x
     when != if (...) { <+...x...+> }
x->f1
...>
(
 return \(0\|<+...x...+>\|ptr\);
|
 return@p2 ...;
)

@script:python@
p1 << r.p1;
p2 << r.p2;
@@

print "* file: %s kmalloc %s return %s" % (p1[0].file,p1[0].line,p2[0].line)
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

arch/powerpc/sysdev/fsl_rmu.c

@@ -1081,6 +1081,7 @@ int fsl_rio_setup_rmu(struct rio_mport *mport, struct device_node *node)
 	if (!msg_addr) {
 		pr_err("%s: unable to find 'reg' property of message-unit\n",
 			node->full_name);
+		kfree(rmu);
 		return -ENOMEM;
 	}
 	msg_start = of_read_number(msg_addr, aw);