kernel: remove CONFIG_USE_GENERIC_SMP_HELPERS cleanly

Remove CONFIG_USE_GENERIC_SMP_HELPERS left by commit 0a06ff068f12
("kernel: remove CONFIG_USE_GENERIC_SMP_HELPERS").

Change-Id: Ia175f191b675b9bc6b1568233bb2712abc889eee
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Git-commit: 044c8d4b15743f6e0a4cb6f2aeb32745a116ebff
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


[lkuch@codeaurora.org: resolve trivial merge conflicts]
Signed-off-by: Liron Kuch <lkuch@codeaurora.org>