wifi: rtl8812au: Fix the problem using the csum_ipv6_magic() function

Change-Id: Ie6430fe47ecf09232e95839ebfb18aded8e8db34

Author: Andy3Kuo

drivers/net/wireless/rockchip_wlan/rtl8812AU_8821AU_linux/core/rtw_br_ext.c

@@ -48,9 +48,13 @@
 #include <linux/ipv6.h>
 #include <linux/icmpv6.h>
 #include <net/ndisc.h>
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 24))
+#include <net/ip6_checksum.h>
+#else
 #include <net/checksum.h>
 #endif
 #endif
+#endif
 
 #ifdef CONFIG_BR_EXT