eal: fix return codes on thread naming failure
eal: fix return codes on thread naming failure

The doc says this function returns negative errno
on error, but it currently returns either -1 or
positive errno.

It was incorrectly assumed that pthread_setname_np()
returns negative error numbers. It always returns
positive ones, so this patch negates its return value
before returning.

Fixes: 3901ed99c2f8 ("eal: fix thread naming on FreeBSD")
Cc: stable@dpdk.org

Signed-off-by: Dariusz Stojaczyk <f11d01fc0f74696e7ca69a73f989fd3bd0b37668@intel.com>
Acked-by: Anatoly Burakov <814e00d8f6e4e81b7ccc7e3e5a0bfec0078f0203@intel.com>
Reviewed-by: Olivier Matz <dfcc1510895413197abb4336e39bb0a3906cba71@6wind.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk