ramips: enable fw_printenv for D-Link COVR-X1860 A1

Vendor U-Boot stores its environment at offset 0x2000 inside the
"config" partition (size 0x4000). The offset is not erase-block
aligned, so the fw_env tool's alignment check rejects the natural
secsize=0x20000. Declaring secsize=0x2000 passes the check, lets
fw_printenv read the real env (factory_mac, hw_version,
bundle_number, ...), and causes fw_setenv to fail cleanly on erase
rather than corrupting anything (the kernel rejects sub-erase-block
MEMERASE).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Signed-off-by: Florian Maurer <fmaurer@disroot.org>
Link: https://github.com/openwrt/openwrt/pull/23192
Signed-off-by: Jonas Jelonek <jelonek.jonas@gmail.com>

package/boot/uboot-tools/uboot-envtools/files/ramips

@@ -44,6 +44,9 @@ arcadyan,we420223-99|\
 dlink,dir-806a-b1)
 	ubootenv_add_uci_config "/dev/mtd2" "0x0" "0x1000" "0x1000"
 	;;
+dlink,covr-x1860-a1)
+	ubootenv_add_uci_config "/dev/mtd1" "0x2000" "0x4000" "0x2000"
+	;;
 asus,rt-ax53u|\
 asus,rt-ax54|\
 asus,4g-ax56|\