mb/siemens/mc_apl2: Enable PCI device for I2C bus 0

On mc_apl2 the external RTC is connected to I2C bus 3. All other I2C bus
devices (16.0, 16.1 and 16.2) have been disabled as they are not used.
While coreboot can handle the case where a PCI device does not have
function 0 enabled but a later one (here function 3), Linux seems to
check for function 0 first and ignores the rest if function 0
is missing. So enable PCI device 16.0 in order to let Linux use 16.3
again.

Test=Boot into Linux and make sure that PCI device 16.0 and 16.3 are
visible and I2C attached RTC works properly.

Change-Id: I55a748b6de8128f4b26b908118feff9f06d3fb7c
Signed-off-by: Werner Zeh <werner.zeh@siemens.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/62215
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Mario Scheithauer <mario.scheithauer@siemens.com>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
diff --git a/src/mainboard/siemens/mc_apl1/variants/mc_apl2/devicetree.cb b/src/mainboard/siemens/mc_apl1/variants/mc_apl2/devicetree.cb
index 7440256..6c17d63 100644
--- a/src/mainboard/siemens/mc_apl1/variants/mc_apl2/devicetree.cb
+++ b/src/mainboard/siemens/mc_apl1/variants/mc_apl2/devicetree.cb
@@ -99,7 +99,7 @@
 		end
 		device pci 15.0 on  end	# - XHCI
 		device pci 15.1 off end	# - XDCI
-		device pci 16.0 off end	# - I2C 0
+		device pci 16.0 on  end	# - I2C 0
 		device pci 16.1 off end	# - I2C 1
 		device pci 16.2 off end	# - I2C 2
 		device pci 16.3 on	# - I2C 3