ARM: multi_v7_defconfig: add OCOTP driver for NXP SoCs

Enable on-chip OTP NVMEM support for NXP i.MX and VF610 SoCs.
Since OTP values might be required by drivers required during
boot, make sure the driver is built-in (e.g. i.MX thermal
driver).

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>