Fixes missing dependency in ss.h on platform.h
Fixes missing dependency in ss.h on platform.h

Fixes #522 - 'mbedtls_time_t does not name a type in ssl.h'

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