Add public getter APIs for mbedtls_cipher_info_t

[gabor-mezei-arm]

As part of #4683, as a result of reviewing the programs there are uses of MBEDTLS_PRIVATE fields of the mbedtls_cipher_info_t structure. To avoid the access of the private fields create and use new public getter APIs for the fields of the mbedtls_cipher_info_t structure.

Accessed fields:

• name
• key_bitlen
• mode

Affected files:

• aes/crypt_and_hash.c

[gilles-peskine-arm]

This was done in #4842.