Only store the first group in ssl_tls13_parse_supported_groups_ext()
Only store the first group in ssl_tls13_parse_supported_groups_ext()

Change-Id: I4427149aeb6eb453150e522e4c7b11187e2e3825
Signed-off-by: XiaokangQian <7b6134ba682adad72773df97eb8737186a67b798@arm.com>

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