generic: drop BUSYBOX_CONFIG_FEATURE_PREFER_IPV4_ADDRESS

These config changes are not necessary anymore, as it's now the default
behavior.

Ref: https://github.com/freifunk-gluon/gluon/pull/2235#issuecomment-859654947


Signed-off-by: David Bauer <mail@david-bauer.net>

targets/generic

@@ -39,9 +39,6 @@ config('ALL_NONSHARED', true)
 config('PACKAGE_usbip', false) -- fails to build
 config('PACKAGE_kmod-jool', false) -- fails to build
 
-config('BUSYBOX_CUSTOM', true)
-config('BUSYBOX_CONFIG_FEATURE_PREFER_IPV4_ADDRESS', false)
-
 try_config('PACKAGE_ATH_DEBUG', true)
 
 try_config('TARGET_SQUASHFS_BLOCK_SIZE', 256)