x86/fpu: Clean up eager_fpu_init() and rename it to fpu__ctx_switch_init()

It's not an xsave specific function anymore, so rename it accordingly
and also clean it up a bit:

 - remove the obsolete __init_refok, as the code paths are not
   mixed anymore

 - rename it from eager_fpu_init() to fpu__ctx_switch_init()

 - remove stray 'return;'

 - make it static to its only user
Reviewed-by: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/fpu/init.c

@@ -167,7 +167,7 @@ __setup("eagerfpu=", eager_fpu_setup);
  * setup_init_fpu_buf() is __init and it is OK to call it here because
  * init_xstate_ctx will be unset only once during boot.
  */
-void __init_refok eager_fpu_init(void)
+static void fpu__ctx_switch_init(void)
 {
 	WARN_ON(current->thread.fpu.fpstate_active);
 	current_thread_info()->status = 0;
@@ -191,10 +191,8 @@ void __init_refok eager_fpu_init(void)
 
 	printk_once(KERN_INFO "x86/fpu: Using '%s' FPU context switches.\n", eagerfpu == ENABLE ? "eager" : "lazy");
 
-	if (!cpu_has_eager_fpu) {
+	if (!cpu_has_eager_fpu)
 		stts();
-		return;
-	}
 }
 
 /*
@@ -214,7 +212,7 @@ void fpu__init_system(void)
 
 	mxcsr_feature_mask_init();
 	fpu__init_system_xstate();
-	eager_fpu_init();
+	fpu__ctx_switch_init();
 }
 
 void fpu__cpu_init(void)