futex: add a struct and a hash list for condvar helpers

Create a futex_h struct associated to each helper task. Lists of
helpers related to different condvars are accessed through a
hash table (futex_helpers) similar to the already present futex_
queues.
futex: add do_futex() FUTEX_COND_HELPER_MAN case

for 3.4:
Add a case in the do_futex() switch. FUTEX_COND_HELPER_MAN calls
futex_helper_manage() that is responsible for add or delete helpers
for a specified condvar.

Conflicts:

	include/uapi/linux/futex.h

Signed-off-by: Luis Cruz <ljc2491@gmail.com>
futex: priority boosting, take 1

Helper vars and code to implement priority (de)boosting for
helper tasks. Try to be compatible with rt_mutexes madness.

Conflicts:

	include/linux/sched.h
	kernel/fork.c

Signed-off-by: Luis Cruz <ljc2491@gmail.com>
futex: priority boosting, take 2
futex: several fixes to boot pi-cv augmented kernel

Mainly realated to spinlocks being not released.
fix syscall params and futex_h alloc
manage private futexes (bugfix with debug output)

Conflicts:

	include/uapi/linux/futex.h

Signed-off-by: Luis Cruz <ljc2491@gmail.com>
inheritance works (with debug output)
Merge branch 'jlelli/pi-cv' into jb-mr1