powerpc/powernv: Add a null pointer check in opal_powercap_init()

kasprintf() returns a pointer to dynamically allocated memory
which can be NULL upon failure.

Fixes: b9ef7b4b ("powerpc: Convert to using %pOFn instead of device_node.name")
Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231126095739.1501990-1-chentao@kylinos.cn

arch/powerpc/platforms/powernv/opal-powercap.c

@@ -196,6 +196,12 @@ void __init opal_powercap_init(void)
 
 		j = 0;
 		pcaps[i].pg.name = kasprintf(GFP_KERNEL, "%pOFn", node);
+		if (!pcaps[i].pg.name) {
+			kfree(pcaps[i].pattrs);
+			kfree(pcaps[i].pg.attrs);
+			goto out_pcaps_pattrs;
+		}
+
 		if (has_min) {
 			powercap_add_attr(min, "powercap-min",
 					  &pcaps[i].pattrs[j]);