x86: Add some missing global_data declarations in files that use gd

Some files use global_data but don't declare it. Fix this.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

arch/x86/lib/lpc-uclass.c

@@ -9,6 +9,8 @@
 #include <dm.h>
 #include <dm/root.h>
 
+DECLARE_GLOBAL_DATA_PTR;
+
 static int lpc_uclass_post_bind(struct udevice *bus)
 {
 	/*