x86/fpu: Move legacy check to fpu__init_system_xstate()

Now that legacy code can execute fpu__init_cpu_xstate() in
xsave_init(), we can move the once per boot legacy check into
fpu__init_system_xstate(), where it belongs.
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/xsave.c

@@ -653,6 +653,11 @@ void fpu__init_system_xstate(void)
 {
 	unsigned int eax, ebx, ecx, edx;
 
+	if (!cpu_has_xsave) {
+		pr_info("x86/fpu: Legacy x87 FPU detected.\n");
+		return;
+	}
+
 	if (boot_cpu_data.cpuid_level < XSTATE_CPUID) {
 		WARN(1, "x86/fpu: XSTATE_CPUID missing!\n");
 		return;
@@ -711,14 +716,6 @@ void xsave_init(void)
 {
 	static char on_boot_cpu = 1;
 
-	if (!cpu_has_xsave) {
-		if (on_boot_cpu) {
-			on_boot_cpu = 0;
-			pr_info("x86/fpu: Legacy x87 FPU detected.\n");
-		}
-		return;
-	}
-
 	if (on_boot_cpu) {
 		on_boot_cpu = 0;
 		fpu__init_system_xstate();