x86/fpu: Propagate once per boot quirk into fpu__init_system_xstate()

Linearize the call sequence in xsave_init():

	fpu__init_system_xstate();
	fpu__init_cpu_xstate();

We do this by propagating the boot-once quirk into
fpu__init_system_xstate(). fpu__init_cpu_xstate() is
safe to be called multiple time.
Reviewed-by: NBorislav 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: NIngo Molnar <mingo@kernel.org>

arch/x86/kernel/fpu/xsave.c

@@ -652,6 +652,11 @@ static void __init init_xstate_size(void)
 void fpu__init_system_xstate(void)
 {
 	unsigned int eax, ebx, ecx, edx;
+	static bool on_boot_cpu = 1;
+
+	if (!on_boot_cpu)
+		return;
+	on_boot_cpu = 0;
 
 	if (!cpu_has_xsave) {
 		pr_info("x86/fpu: Legacy x87 FPU detected.\n");
@@ -714,14 +719,8 @@ void fpu__init_system_xstate(void)
  */
 void xsave_init(void)
 {
-	static char on_boot_cpu = 1;
-
-	if (on_boot_cpu) {
-		on_boot_cpu = 0;
-		fpu__init_system_xstate();
-	} else {
-		fpu__init_cpu_xstate();
-	}
+	fpu__init_system_xstate();
+	fpu__init_cpu_xstate();
 }
 
 /*