block,elevator: use new hashtable implementation

Switch elevator to use the new hashtable implementation. This reduces the
amount of generic unrelated code in the elevator.

This also removes the dymanic allocation of the hash table. The size of the table is
constant so there's no point in paying the price of an extra dereference when accessing
it.

This patch depends on d9b482c ("hashtable: introduce a small and naive
hashtable") which was merged in v3.6.

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
Signed-off-by: Seongmin Park <r_data@naver.com>
cpufreq_wheatley.c: Fix build error and warning messages

Signed-off-by: Seongmin Park <r_data@naver.com>
hashtable: introduce a small and naive hashtable

This hashtable implementation is using hlist buckets to provide a simple
hashtable to prevent it from getting reimplemented all over the kernel.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
[ Merging this now, so that subsystems can start applying Sasha's
  patches that use this   - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
Signed-off-by: Seongmin Park <r_data@naver.com>
Revert "timekeeping: Provide hrtimer update function"

This reverts commit 765bdc4d82fadcddfec19222a545e904633c7816.
Revert "hrtimer: Provide clock_was_set_delayed()"

This reverts commit 5e5006e64cae9603841405af9febb67064869d83.
Makefile: Change toolchain

Signed-off-by: Seongmin Park <r_data@naver.com>