Store the TLS version in tls_version instead of major, minor version num
Note: existing application use which accesses the struct member
(using MBEDTLS_PRIVATE) is not compatible, as the struct is now smaller.
Reduce size of mbedtls_ssl_ciphersuite_t
members are defined using integral types instead of enums in
order to pack structure and reduce memory usage by internal
ciphersuite_definitions[]
Signed-off-by: Glenn Strauss <gstrauss@gluelogic.com>