kernel: remove CONFIG_USE_GENERIC_SMP_HELPERS

kernel: remove CONFIG_USE_GENERIC_SMP_HELPERS

We've switched over every architecture that supports SMP to it, so
remove the new useless config variable.

Conflicts:
	arch/arm/Kconfig
	block/blk-mq.c
Change-Id: Ic19c3ac07a38a1636d6aa2fed5e55a58833f9b2c
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit 0a06ff068f1255bcd7965ab07bc0f4adc3eb639a)
Signed-off-by: Ishan Mittal <imittal@nvidia.com>