The long-term goal of the Zephyr project is to rely exclusively on PSA Crypto API for the crypto support. In parallel Mbed TLS is going to remove legacy crypto support from the next (4.0) release. Therefore this commit deprecates CONFIG_FLASH_AREA_CHECK_INTEGRITY_MBEDTLS and it also updates the migration guide document about this change. Signed-off-by: Valerio Setti <vsetti@baylibre.com>