x86: Add missing DECLARE_GLOBAL_DATA_PTR for pci.c

arch/x86/cpu/pci.c has access to the U-Boot global data thus
DECLARE_GLOBAL_DATA_PTR is needed.

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

arch/x86/cpu/pci.c

@@ -15,6 +15,8 @@
 #include <pci.h>
 #include <asm/pci.h>
 
+DECLARE_GLOBAL_DATA_PTR;
+
 static struct pci_controller x86_hose;
 
 int pci_early_init_hose(struct pci_controller **hosep)