x86: Remove gdt_addr from arch_global_data

Remove this unused field.

Signed-off-by: Simon Glass <sjg@chromium.org>

arch/x86/include/asm/global_data.h

@@ -61,7 +61,6 @@ struct global_data {
 	unsigned long	bus_clk;
 	unsigned long	relocaddr;	/* Start address of U-Boot in RAM */
 	unsigned long	start_addr_sp;	/* start_addr_stackpointer */
-	unsigned long	gdt_addr;	/* Location of GDT */
 	phys_size_t	ram_size;	/* RAM size */
 	unsigned long	reset_status;	/* reset status register at boot */
 	const void	*fdt_blob;	/* Our device tree, NULL if none */