kho: kho_preserve_vmalloc(): don't return 0 when ENOMEM

kho_preserve_vmalloc() should return -ENOMEM when new_vmalloc_chunk()
fails.

Reported-by: kernel test robot <[e-mail]>
Reported-by: Dan Carpenter <[e-mail]>
Closes: https://lore.kernel.org/r/[e-mail]/
Reviewed-by: Pasha Tatashin <[e-mail]>
Reviewed-by: Pratyush Yadav <[e-mail]>
Reviewed-by: Mike Rapoport (Microsoft) <[e-mail]>
Cc: Alexander Graf <[e-mail]>
Cc: Jason Gunthorpe <[e-mail]>
Cc: Pasha Tatashin <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

kernel/liveupdate/kexec_handover.c

···
 		chunk->phys[idx++] = phys;
 		if (idx == ARRAY_SIZE(chunk->phys)) {
 			chunk = new_vmalloc_chunk(chunk);
-			if (!chunk)
+			if (!chunk) {
+				err = -ENOMEM;
 				goto err_free;
+			}
 			idx = 0;
 		}
 	}