Get rid of local variable cpu_num as it is equal to @cpu now. Deref
cpu_data() only when it is really needed at the end.

No functionality change.
Tested-by: NThomas Voegtle <tv@lio96.de>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1454499225-21544-12-git-send-email-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>