powerpc/smp: Drop superfluous NULL check

We don't need the NULL check of np, the result is the same because the
OF helpers cope with NULL, of_node_to_nid(NULL) == NUMA_NO_NODE (-1).
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200313112020.28235-1-mpe@ellerman.id.au

arch/powerpc/kernel/smp.c

@@ -1197,11 +1197,8 @@ int get_physical_package_id(int cpu)
 	 */
 	if (pkg_id == -1 && firmware_has_feature(FW_FEATURE_LPAR)) {
 		struct device_node *np = of_get_cpu_node(cpu, NULL);
-
-		if (np) {
-			pkg_id = of_node_to_nid(np);
-			of_node_put(np);
-		}
+		pkg_id = of_node_to_nid(np);
+		of_node_put(np);
 	}
 #endif /* CONFIG_PPC_SPLPAR */