apm821xx: NETGEAR WNDR4700: Fix compat version

The definition for the netgear_wndr4700 had two different
DEVICE_COMPAT_VERSION definitions.

In commit 5815884c3a2 ("apm821xx: migrate to DSA"), an additional
DEVICE_COMPAT_VERSION := 3.0 attribute was added to the device
definition. The old one with version 2.0 stayed and was defined later
overwriting the new one.

Replace the old version 2.0 with the new version 3.0

Fixes: 5815884c3a2a ("apm821xx: migrate to DSA")
Link: https://forum.openwrt.org/t/openwrt-24-10-0-rc6-sixth-release-candidate/222466/43
Link: https://github.com/openwrt/openwrt/pull/17741
Signed-off-by: Hauke Mehrtens <[email protected]>

target/linux/apm821xx/image/nand.mk

@@ -89,9 +89,6 @@ endef
 TARGET_DEVICES += netgear_wndap660
 
 define Device/netgear_wndr4700
-  DEVICE_COMPAT_VERSION := 3.0
-  DEVICE_COMPAT_MESSAGE := Network swconfig configuration cannot be upgraded to DSA. \
-       Upgrade via sysupgrade mechanism is not possible.
   DEVICE_VENDOR := NETGEAR
   DEVICE_MODEL := Centria N900 WNDR4700
   DEVICE_ALT0_VENDOR := NETGEAR
@@ -123,8 +120,9 @@ define Device/netgear_wndr4700
   NETGEAR_HW_ID := 29763875+128+256
   UBINIZE_OPTS := -E 5
   SUPPORTED_DEVICES += wndr4700
-  DEVICE_COMPAT_VERSION := 2.0
+  DEVICE_COMPAT_VERSION := 3.0
   DEVICE_COMPAT_MESSAGE := kernel and ubi partitions had to be resized. \
+       Network swconfig configuration cannot be upgraded to DSA. \
        Upgrade via sysupgrade mechanism is not possible.
 endef
 TARGET_DEVICES += netgear_wndr4700