x86: Remove init_gd() function

This is declared but no-longer exists. Drop it.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/x86/include/asm/u-boot-x86.h b/arch/x86/include/asm/u-boot-x86.h
index 4dae365..1c459d5 100644
--- a/arch/x86/include/asm/u-boot-x86.h
+++ b/arch/x86/include/asm/u-boot-x86.h
@@ -14,7 +14,6 @@
 int arch_cpu_init(void);
 int x86_cpu_init_f(void);
 int cpu_init_f(void);
-void init_gd(gd_t *id, u64 *gdt_addr);
 void setup_gdt(gd_t *id, u64 *gdt_addr);
 /*
  * Setup FSP execution environment GDT to use the one we used in