papi_native_avail: fix empty component case
papi_native_avail: fix empty component case

If a component had no events, papi_native_avail would ignore
the error returned by
   PAPI_enum_cmp_event( PAPI_ENUM_FIRST );
and try to print a first event anyway.

arm-hpc/papi,arm-hpc/papi,arm-hpc/papi,arm-hpc/papi,arm-hpc/papi,arm-hpc/papi,arm-hpc/papi