uboot-envtools: fix Edimax BR-6425 board name

Signed-off-by: Piotr Dymacz <[email protected]>

package/boot/uboot-envtools/files/ramips

@@ -19,7 +19,7 @@ all0256n|\
 all5002)
 	ubootenv_add_uci_config "/dev/mtd1" "0x0" "0x10000" "0x10000"
 	;;
-br6425|\
+br-6425|\
 linkits7688|\
 linkits7688d|\
 miwifi-nano|\