kernel/semaphore: add new APIs for priority inheritance
This commit introduces new APIs, pthread_mutexattr_get/set_protocol and
non-standard sem_get/set_protocol, which allow to enable or disable
priority inheritance on a single semaphore. Backported from NuttX. All
credits should go to Gregory Nutt who wrote the original patch.
Change-Id: I05c62a6a4ee6fbdb00b0478bf8ef8cfe44487f92
Signed-off-by: Gregory Nutt <gnutt@nuttx.org>
[Shin: backported
92d30224 from the upstream]
Signed-off-by: Heesub Shin <heesub.shin@samsung.com>