ar71xx: image: fix DEVICE_TITLE for several devices

Be consistent with form and format of the vendor names.

Signed-off-by: Piotr Dymacz <pepe2k@gmail.com>

target/linux/ar71xx/image/generic.mk

@@ -427,7 +427,7 @@ TARGET_DEVICES += rnx-n360rt
 
 define Device/mc-mac1200r
   $(Device/tplink-8mlzma)
-  DEVICE_TITLE := MERCURY MAC1200R
+  DEVICE_TITLE := Mercury MAC1200R
   DEVICE_PACKAGES := kmod-ath10k ath10k-firmware-qca988x
   BOARDNAME := MC-MAC1200R
   DEVICE_PROFILE := MAC1200R

target/linux/ar71xx/image/legacy-devices.mk

@@ -328,7 +328,7 @@ endef
 LEGACY_DEVICES += WRT160NL
 
 define LegacyDevice/MYNETREXT
-  DEVICE_TITLE := WD My Net Wi-Fi Range Extender
+  DEVICE_TITLE := Western Digital My Net Wi-Fi Range Extender
   DEVICE_PACKAGES := rssileds
 endef
 LEGACY_DEVICES += MYNETREXT
@@ -640,7 +640,7 @@ endef
 LEGACY_DEVICES += ZCN1523H516
 
 define LegacyDevice/NBG_460N_550N_550NH
-  DEVICE_TITLE := Zyxel NBG 460N/550N/550NH
+  DEVICE_TITLE := ZyXEL NBG 460N/550N/550NH
   DEVICE_PACKAGES := kmod-rtc-pcf8563
 endef
 LEGACY_DEVICES += NBG_460N_550N_550NH

target/linux/ar71xx/image/tp-link.mk

@@ -602,7 +602,7 @@ endef
 
 define Device/tl-wr810n
     $(Device/tplink-8mlzma)
-    DEVICE_TITLE := TP-Link TL-WR810N
+    DEVICE_TITLE := TP-LINK TL-WR810N
     DEVICE_PACKAGES := kmod-usb-core kmod-usb2
     BOARDNAME := TL-WR810N
     DEVICE_PROFILE := TLWR810