[PATCH] powerpc: hwrng; fix missing of_node_put()

[Nicholas Mc Guire]

 The call to of_find_compatible_node() returns a node pointer with refcount
incremented thus it must be explicitly decremented here before returning.

Signed-off-by: Nicholas Mc Guire <hofrat@xxxxxxxxx>
Fixes: commit a489043f4626 ("powerpc/pseries: Implement arch_get_random_long() based on H_RANDOM")
---
Problem found with experimental coccinelle script

Patch was compiletested with: ppc64_defconfig (implies CONFIG_PPC_PSERIES=y)
with some unrelated sparse warnings (which I did not understand)
./arch/powerpc/include/asm/head-64.h:13:36: warning: Unknown escape '('
./arch/powerpc/include/asm/head-64.h:16:36: warning: Unknown escape '('
./arch/powerpc/include/asm/head-64.h:19:36: warning: Unknown escape '('

Patch is aginst 4.18-rc2 (localversion-next is next-20180702)

 arch/powerpc/platforms/pseries/rng.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/powerpc/platforms/pseries/rng.c b/arch/powerpc/platforms/pseries/rng.c
index 31ca557..262b8c5 100644
--- a/arch/powerpc/platforms/pseries/rng.c
+++ b/arch/powerpc/platforms/pseries/rng.c
@@ -40,6 +40,7 @@ static __init int rng_init(void)
 
 	ppc_md.get_random_seed = pseries_get_random_long;
 
+	of_node_put(dn);
 	return 0;
 }
 machine_subsys_initcall(pseries, rng_init);
-- 
2.1.4