nvmem: stm32: add nvmem type attribute

Inform NVMEM framework of type attribute for stm32-romem as NVMEM_TYPE_OTP
so userspace is able to know how the data is stored in BSEC.

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20221118063932.6418-4-srinivas.kandagatla@linaro.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>