* Simplify EINTR/ECANCEL error handling
1. Add semaphore uninterruptible wait function
2 .Replace semaphore wait loop with a single uninterruptible wait
3. Replace all sem_xxx to nxsem_xxx
* Unify the void cast usage
1. Remove void cast for function because many place ignore the returned value witout cast
2. Replace void cast for variable with UNUSED macro
Iobinstrumentation
* mm/iob: Introduces producer/consumer id to every iob call. This is so that the calls can be instrumented to monitor the IOB resources.
* iob instrumentation - Merges producer/consumer enumeration for simpler IOB user.
* fs/procfs: Starts adding support for /proc/iobinfo
* fs/procfs: Finishes first pass of simple IOB user stastics and /proc/iobinfo entry
Approved-by: Gregory Nutt <gnutt@nuttx.org>
