vexpress64: compile Juno PCIe conditionally

Only compile in PCIe support if the board really uses it. Provide
a __weak stub for the init function if e.g. FVP is being built.

Signed-off-by: Ryan Harkin <ryan.harkin@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>

board/armltd/vexpress64/Makefile

@@ -5,4 +5,5 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-obj-y	:= vexpress64.o pcie.o
+obj-y	:= vexpress64.o
+obj-$(CONFIG_TARGET_VEXPRESS64_JUNO)	+= pcie.o

board/armltd/vexpress64/pcie.c

@@ -191,7 +191,5 @@ void xr3pci_init(void)
 
 void vexpress64_pcie_init(void)
 {
-#ifdef CONFIG_TARGET_VEXPRESS64_JUNO
 	xr3pci_init();
-#endif
 }

board/armltd/vexpress64/vexpress64.c

@@ -28,6 +28,13 @@ U_BOOT_DEVICE(vexpress_serials) = {
 	.platdata = &serial_platdata,
 };
 
+/* This function gets replaced by platforms supporting PCIe.
+ * The replacement function, eg. on Juno, initialises the PCIe bus.
+ */
+__weak void vexpress64_pcie_init(void)
+{
+}
+
 int board_init(void)
 {
 	vexpress64_pcie_init();