arm64: Only enable local interrupts after the CPU is marked online

There is a slight chance that (timer) interrupts are triggered before a
secondary CPU has been marked online with implications on softirq thread
affinity.

Change-Id: I9d8e805f392d761b4427bbd6235c17d33bb9df23
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Kirill Tkhai <tkhai@yandex.ru>
Git-commit: 53ae3acd4390ffeecb3a11dbd5be347b5a3d98f2
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git


Signed-off-by: Abhimanyu Kapur <abhimany@codeaurora.org>