iommu: fsl_pamu.c: Fix for possible null pointer dereference

There is otherwise a risk of a possible null pointer dereference.

Was largely found by using a static code analysis program called cppcheck.
Signed-off-by: NRickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Reviewed-by: NBharat Bhushan <bharat.bhushan@freescale.com>
Acked-by: NVarun Sethi <Varun.Sethi@freescale.com>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>

drivers/iommu/fsl_pamu.c

@@ -592,8 +592,7 @@ u32 get_stash_id(u32 stash_dest_hint, u32 vcpu)
 		/* advance to next node in cache hierarchy */
 		node = of_find_node_by_phandle(*prop);
 		if (!node) {
-			pr_debug("Invalid node for cache hierarchy %s\n",
-				node->full_name);
+			pr_debug("Invalid node for cache hierarchy\n");
 			return ~(u32)0;
 		}
 	}