[PATCH] Make kstat_this_cpu in terms of __get_cpu_var and use it

[PATCH] Make kstat_this_cpu in terms of __get_cpu_var and use it

kstat_this_cpu() is defined in terms of per_cpu instead of __get_cpu_var.

This patch changes that, and uses it everywhere appropriate.  The sched.c
change puts it in a local variable, which helps gcc generate better code.