This indicates integer counter mode being used and
helps disambiguate additional crypto suites in the future.
Renamed CALLS_SRTP_SUITE_AES_128_SHA1_80 → CALLS_SRTP_SUITE_AES_128_ICM_SHA1_80
and CALLS_SRTP_SUITE_AES_128_SHA1_32 → CALLS_SRTP_SUITE_AES_128_ICM_SHA1_32