__this_cpu_ptr is being phased out.

One special case is increment_cpu_stall_ticks().
A per cpu variable is incremented so use raw_cpu_inc().

Cc: Dipankar Sarma <dipankar@in.ibm.com>
Signed-off-by: NChristoph Lameter <cl@linux.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>