nvmem: allow to select i.MX nvmem driver for i.MX 7D

The imx-ocotp nvmem driver supports the i.MX 7D SoC too. Allow to select
the imx-ocotp driver even if only the i.MX 7D SoC has been selected.

Fixes: 711d4547 ("nvmem: octop: Add i.MX7D support")
Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>