package/pcm-tools: needs NPTL

pcm-tools needs NPTL since its addition in commit
60eb2cec:

cpucounters.cpp: In constructor 'pcm::TemporalThreadAffinity::TemporalThreadAffinity(pcm::uint32, bool)':
cpucounters.cpp:252:9: error: 'pthread_getaffinity_np' was not declared in this scope; did you mean 'sched_getaffinity'?
  252 |         pthread_getaffinity_np(pthread_self(), set_size, old_affinity);
      |         ^~~~~~~~~~~~~~~~~~~~~~
      |         sched_getaffinity

Fixes:
 - http://autobuild.buildroot.org/results/8bbf9c36af332bbf5e7c1abcbb594a0b231ef97e



Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>