mvebu: WD Cloud Mirror Gen2: Remove stty dependency

The package coreutils-stty is not part of the OpenWrt main packages. A
board can not depend on it. Remove the dependency to fix a build problem
seen in the build bots.

Fixes: 8fb805aa1f25 ("mvebu: Add support for WD Cloud Mirror Gen2")
(cherry picked from commit 717f62d256ccb52549a24c256615b28440ed1a86)
Link: https://github.com/openwrt/openwrt/pull/17589
Signed-off-by: Hauke Mehrtens <[email protected]>

target/linux/mvebu/image/cortexa9.mk

@@ -453,7 +453,7 @@ define Device/wd_cloud-mirror-gen2
   $(Device/NAND-128K)
   DEVICE_VENDOR := Western Digital
   DEVICE_MODEL := MyCloud Mirror Gen 2 (BWVZ/Grand Teton)
-  DEVICE_PACKAGES += -uboot-envtools coreutils-stty mkf2fs e2fsprogs \
+  DEVICE_PACKAGES += -uboot-envtools mkf2fs e2fsprogs \
 	partx-utils kmod-hwmon-drivetemp -ppp -kmod-nft-offload -dnsmasq \
 	-odhcpd-ipv6only 
   DEVICE_DTS := armada-385-wd_cloud-mirror-gen2