percpu: add preemption checks to __this_cpu ops

percpu: add preemption checks to __this_cpu ops

We define a check function in order to avoid trouble with the include
files.  Then the higher level __this_cpu macros are modified to invoke
the preemption check.

[[email protected]: coding-style fixes]
Signed-off-by: Christoph Lameter <[email protected]>
Acked-by: Ingo Molnar <[email protected]>
Cc: Tejun Heo <[email protected]>
Tested-by: Grygorii Strashko <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>