r8169: fix building with CONFIG_LEDS_CLASS=m

When r8169 is built-in but LED support is a loadable module, the new
code to drive the LED causes a link failure:

ld: drivers/net/ethernet/realtek/r8169_leds.o: in function `rtl8168_init_leds':
r8169_leds.c:(.text+0x36c): undefined reference to `devm_led_classdev_register_ext'

LED support is an optional feature, so fix this issue by adding a Kconfig
symbol R8169_LEDS that is guaranteed to be false if r8169 is built-in
and LED core support is a module. As a positive side effect of this change
r8169_leds.o no longer is built under this configuration.

Fixes: 18764b8 ("r8169: add support for LED's on RTL8168/RTL8101")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202312281159.9TPeXbNd-lkp@intel.com/
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Tested-by: Simon Horman <horms@kernel.org> # build-tested
Tested-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/d055aeb5-fe5c-4ccf-987f-5af93a17537b@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/realtek/Kconfig

@@ -113,4 +113,11 @@ config R8169
 	  To compile this driver as a module, choose M here: the module
 	  will be called r8169.  This is recommended.
 
+config R8169_LEDS
+	def_bool R8169 && LEDS_TRIGGER_NETDEV
+	depends on !(R8169=y && LEDS_CLASS=m)
+	help
+	  Optional support for controlling the NIC LED's with the netdev
+	  LED trigger.
+
 endif # NET_VENDOR_REALTEK

drivers/net/ethernet/realtek/Makefile

@@ -6,8 +6,6 @@
 obj-$(CONFIG_8139CP) += 8139cp.o
 obj-$(CONFIG_8139TOO) += 8139too.o
 obj-$(CONFIG_ATP) += atp.o
-r8169-objs += r8169_main.o r8169_firmware.o r8169_phy_config.o
-ifdef CONFIG_LEDS_TRIGGER_NETDEV
-r8169-objs += r8169_leds.o
-endif
+r8169-y += r8169_main.o r8169_firmware.o r8169_phy_config.o
+r8169-$(CONFIG_R8169_LEDS) += r8169_leds.o
 obj-$(CONFIG_R8169) += r8169.o

drivers/net/ethernet/realtek/r8169_main.c

@@ -5356,11 +5356,10 @@ static int rtl_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 	if (rc)
 		return rc;
 
-#if IS_REACHABLE(CONFIG_LEDS_CLASS) && IS_ENABLED(CONFIG_LEDS_TRIGGER_NETDEV)
-	if (tp->mac_version > RTL_GIGA_MAC_VER_06 &&
+	if (IS_ENABLED(CONFIG_R8169_LEDS) &&
+	    tp->mac_version > RTL_GIGA_MAC_VER_06 &&
 	    tp->mac_version < RTL_GIGA_MAC_VER_61)
 		rtl8168_init_leds(dev);
-#endif
 
 	netdev_info(dev, "%s, %pM, XID %03x, IRQ %d\n",
 		    rtl_chip_infos[chipset].name, dev->dev_addr, xid, tp->irq);