Update LMS calculate_public_key docs
Update LMS calculate_public_key docs

To avoid the word "generate"

Signed-off-by: Raef Coles <2c10e0e6f5374901a23c5e89def58f720f02d7de@arm.com>

Mbed-TLS/mbedtls,ARMmbed/mbedtls,Mbed-TLS/mbedtls,ARMmbed/mbedtls,Mbed-TLS/mbedtls,ARMmbed/mbedtls,ARMmbed/mbedtls,Mbed-TLS/mbedtls