Add a Kconfig option to match the Mbed TLS define
instead of defining it based on CONFIG_SECURE_STORAGE.
This gives more flexibility regarding the potential re-definition of the
CONFIG_MBEDTLS_PSA_CRYPTO_STORAGE_C Kconfig option.
Signed-off-by: Tomi Fontanilles <tomi.fontanilles@nordicsemi.no>
`SECURE_STORAGE_ITS_STORE_IMPLEMENTATION_SETTINGS` does not use either
the `FLASH_MAP` or `NVS` APIs, only `SETTINGS`.
Similarly, `SECURE_STORAGE_ITS_STORE_MODULE` does not consist of any
code itself and therefore should not select or imply any options.
Signed-off-by: Jordan Yates <jordan@embeint.com>