Per-execution-context freelists

Global free cacheline list is divided into a set of freelists, one
per execution context. When attempting to map addres to cache, first
the freelist for current execution context is considered (fast path).
If current execution context freelist is empty (fast path failure),
mapping function attempts to get freelist from other execution context
list (slow path).

The purpose of this change is improve concurrency in freelist access.
It is part of fine granularity metadata lock implementation.

Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>

env/posix/ocf_env.h

@@ -653,5 +653,4 @@ unsigned env_get_execution_context(void);
 void env_put_execution_context(unsigned ctx);
 unsigned env_get_execution_context_count(void);
 
-
 #endif /* __OCF_ENV_H__ */