nvmem: sunxi_sid: return -ENOMEM if kzalloc() fails

The driver currently returns -EINVAL if kzalloc() fails in probe().
Change it to -ENOMEM as it should be.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>