base: host side mutex contention

This reduces the chances of mutex lock contention on the host-side which becomes
apparent when a large number of pthreads are created and access the mutex
simultaneously.

Signed-off-by: Yuji Mano <yuji.mano@am.sony.com>
Acked-by: Kazunori Asayama <asayama@sm.sony.co.jp>