ramips: set uImage name of WeVO 11AC NAS and W2914NS v2

The stock firmware and bootloader only accept uImage with names that
match certain patterns. This patch enables OpenWrt installation from
stock firmware without having to reflash the bootloader or access the
UART console.

Installation via web interface:
1.  Flash **initramfs** image through the stock web interface.
2.  Boot into OpenWrt and perform sysupgrade with sysupgrade image.

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

target/linux/ramips/image/mt7621.mk

@@ -738,6 +738,7 @@ TARGET_DEVICES += unielec_u7621-06-64m
 define Device/wevo_11acnas
   MTK_SOC := mt7621
   IMAGE_SIZE := 16064k
+  UIMAGE_NAME := 11AC-NAS-Router(0.0.0)
   DEVICE_VENDOR := WeVO
   DEVICE_MODEL := 11AC NAS Router
   DEVICE_PACKAGES := kmod-mt7603 kmod-mt76x2 kmod-usb3 kmod-usb-ledtrig-usbport wpad-basic
@@ -748,6 +749,7 @@ TARGET_DEVICES += wevo_11acnas
 define Device/wevo_w2914ns-v2
   MTK_SOC := mt7621
   IMAGE_SIZE := 16064k
+  UIMAGE_NAME := W2914NS-V2(0.0.0)
   DEVICE_VENDOR := WeVO
   DEVICE_MODEL := W2914NS
   DEVICE_VARIANT := v2