kernel: replace "+@" IPV6 dependency by "+"

The combination +@IPV6:kmod-ipsec6 is not valid, the +a:b
syntax implies the @. Fix it.

Fixes: 2e6b6f9fca ("kernel: add @IPv6 dependency to ipv6 modules")

Reported-by: Oldřich Jedlička (@oldium)
Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>

package/kernel/linux/modules/netsupport.mk

@@ -399,7 +399,7 @@ $(eval $(call KernelPackage,ip6-vti))
 define KernelPackage/xfrm-interface
   SUBMENU:=$(NETWORK_SUPPORT_MENU)
   TITLE:=IPsec XFRM Interface
-  DEPENDS:=+kmod-ipsec4 +@IPV6:kmod-ipsec6 @!LINUX_4_14
+  DEPENDS:=+kmod-ipsec4 +IPV6:kmod-ipsec6 @!LINUX_4_14
   KCONFIG:=CONFIG_XFRM_INTERFACE
   FILES:=$(LINUX_DIR)/net/xfrm/xfrm_interface.ko
   AUTOLOAD:=$(call AutoProbe,xfrm_interface)