x86, fpu: Change __thread_fpu_begin() to use use_eager_fpu()

__thread_fpu_begin() checks X86_FEATURE_EAGER_FPU by hand, we have
a helper for that.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Link: http://lkml.kernel.org/r/20140902175720.GA21656@redhat.com
Reviewed-by: Suresh Siddha <sbsiddha@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

arch/x86/include/asm/fpu-internal.h

@@ -344,7 +344,7 @@ static inline void __thread_fpu_end(struct task_struct *tsk)
 
 static inline void __thread_fpu_begin(struct task_struct *tsk)
 {
-	if (!static_cpu_has_safe(X86_FEATURE_EAGER_FPU))
+	if (!use_eager_fpu())
 		clts();
 	__thread_set_has_fpu(tsk);
 }