x86: Move turbo_state to global_data

To avoid using BSS in SPL before SDRAM is set up, move this field to
global_data.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/x86/cpu/turbo.c b/arch/x86/cpu/turbo.c
index 254d0de..bbd255e 100644
--- a/arch/x86/cpu/turbo.c
+++ b/arch/x86/cpu/turbo.c
@@ -12,6 +12,8 @@
 #include <asm/processor.h>
 #include <asm/turbo.h>
 
+DECLARE_GLOBAL_DATA_PTR;
+
 #if CONFIG_CPU_INTEL_TURBO_NOT_PACKAGE_SCOPED
 static inline int get_global_turbo_state(void)
 {
@@ -22,16 +24,14 @@
 {
 }
 #else
-static int g_turbo_state = TURBO_UNKNOWN;
-
 static inline int get_global_turbo_state(void)
 {
-	return g_turbo_state;
+	return gd->arch.turbo_state;
 }
 
 static inline void set_global_turbo_state(int state)
 {
-	g_turbo_state = state;
+	gd->arch.turbo_state = state;
 }
 #endif