sched/core: Remove the tsk_cpus_allowed() wrapper

So the original intention of tsk_cpus_allowed() was to 'future-proof'
the field - but it's pretty ineffectual at that, because half of
the code uses ->cpus_allowed directly ...

Also, the wrapper makes the code longer than the original expression!

So just get rid of it. This also shrinks <linux/sched.h> a bit.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/sparc/kernel/sysfs.c

@@ -106,7 +106,7 @@ static unsigned long run_on_cpu(unsigned long cpu,
 	cpumask_t old_affinity;
 	unsigned long ret;
 
-	cpumask_copy(&old_affinity, tsk_cpus_allowed(current));
+	cpumask_copy(&old_affinity, &current->cpus_allowed);
 	/* should return -EINVAL to userspace */
 	if (set_cpus_allowed_ptr(current, cpumask_of(cpu)))
 		return 0;