Merge pull request #18370 from miri64/gnrc_netif_conf/fix/6ctx-switch

gnrc_netif_conf: fix auto-6ctx switch

Author: miri64

sys/include/net/gnrc/netif/conf.h

@@ -200,9 +200,11 @@ extern "C" {
  * When set, 6LoWPAN compression context 0 will be automatically set for the prefix configured by
  * prefix deligation at the border router.
  */
+#if !IS_ACTIVE(CONFIG_KCONFIG_USEMODULE_GNRC_NETIF)
 #ifndef CONFIG_GNRC_NETIF_IPV6_BR_AUTO_6CTX
 #define CONFIG_GNRC_NETIF_IPV6_BR_AUTO_6CTX   1
 #endif
+#endif
 
 #ifdef __cplusplus
 }