ramips: rename mtd partition of ipTIME NAND devices

Contrary to common ipTIME NOR devices, the "Config" partition of T5004
and AX2004M contain normal U-Boot environment variables. Renaming the
partition into "u-boot-env" serves for better description, and it also
conforms to common naming practice in OpenWrt.

This patch might also be extended to A3004T, but its u-boot-env
partition layout has not been confirmed yet.

Signed-off-by: Sungbo Eo <mans0n@gorani.run>

package/boot/uboot-envtools/files/ramips

@@ -73,6 +73,7 @@ belkin,rt1800|\
 h3c,tx1800-plus|\
 h3c,tx1801-plus|\
 h3c,tx1806|\
+iptime,ax2004m|\
 jcg,q20|\
 linksys,e7350|\
 netgear,eax12|\
@@ -92,6 +93,7 @@ ravpower,rp-wd03)
 		ubootenv_add_uci_config "/dev/mtd$idx" "0x4000" "0x1000" "0x1000"
 	;;
 beeline,smartbox-flash|\
+iptime,t5004|\
 linksys,ea6350-v4|\
 linksys,ea7300-v1|\
 linksys,ea7300-v2|\