libspdm_get_measurement_extension_log unresolved in do_measurement_mel_via_spdm if LIBSPDM_ENABLE_CAPABILITY_MEL_CAP is not supported.

[tmarkey64]

The call to libspdm_get_measurement_extension_log in do_measurement_mel_via_spdm needs a #if LIBSPDM_ENABLE_CAPABILITY_MEL_CAP in case the capability is not available.