sandbox: pci: Move pci_offset_to_barnum() to pci.h

This function is useful in PCI emulators. More it into the header file to
avoid duplicating it in other drivers.

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

include/pci.h

@@ -215,6 +215,10 @@
 #define  PCI_BASE_ADDRESS_IO_MASK	(~0x03ULL)
 /* bit 1 is reserved if address_space = 1 */
 
+/* Convert a regsister address (e.g. PCI_BASE_ADDRESS_1) to a bar # (e.g. 1) */
+#define pci_offset_to_barnum(offset)	\
+		(((offset) - PCI_BASE_ADDRESS_0) / sizeof(u32))
+
 /* Header type 0 (normal devices) */
 #define PCI_CARDBUS_CIS		0x28
 #define PCI_SUBSYSTEM_VENDOR_ID 0x2c