Add mt7621 6.1 support

6.1/target/linux/ramips/patches-6.1/315-owrt-hack-fix-mt7688-cache-issue.patch

@@ -0,0 +1,28 @@
+From 5ede027f6c4a57ed25da872420508b7f1168b36b Mon Sep 17 00:00:00 2001
+From: John Crispin <blogic@openwrt.org>
+Date: Mon, 7 Dec 2015 17:15:32 +0100
+Subject: [PATCH 13/53] owrt: hack: fix mt7688 cache issue
+
+Signed-off-by: John Crispin <blogic@openwrt.org>
+---
+ arch/mips/kernel/setup.c |    2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+--- a/arch/mips/kernel/setup.c
++++ b/arch/mips/kernel/setup.c
+@@ -686,7 +686,6 @@ static void __init arch_mem_init(char **
+ 	mips_reserve_vmcore();
+ 
+ 	mips_parse_crashkernel();
+-	device_tree_init();
+ 
+ 	/*
+ 	 * In order to reduce the possibility of kernel panic when failed to
+@@ -803,6 +802,7 @@ void __init setup_arch(char **cmdline_p)
+ 
+ 	cpu_cache_init();
+ 	paging_init();
++	device_tree_init();
+ 
+ 	memblock_dump_all();
+ }