kernel: migrate wireguard into the kernel tree

On Linux 5.4, build WireGuard from backports. Linux 5.10 contains
wireguard in-tree.

Add in-kernel crypto libraries required by WireGuard along with
arch-specific optimizations.

Signed-off-by: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>

package/network/services/wireguard/Makefile

@@ -1,88 +0,0 @@
-#
-# Copyright (C) 2016-2019 Jason A. Donenfeld <Jason@zx2c4.com>
-# Copyright (C) 2016 Baptiste Jonglez <openwrt@bitsofnetworks.org>
-# Copyright (C) 2016-2017 Dan Luedtke <mail@danrl.com>
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-
-include $(TOPDIR)/rules.mk
-include $(INCLUDE_DIR)/kernel.mk
-
-PKG_NAME:=wireguard
-
-PKG_VERSION:=1.0.20201112
-PKG_RELEASE:=1
-
-PKG_SOURCE:=wireguard-linux-compat-$(PKG_VERSION).tar.xz
-PKG_SOURCE_URL:=https://git.zx2c4.com/wireguard-linux-compat/snapshot/
-PKG_HASH:=89eae7f0c0bd6c8df3ba2e090984974ff68741a9f26aa0922890f8ca727897e1
-
-PKG_LICENSE:=GPL-2.0
-PKG_LICENSE_FILES:=COPYING
-
-PKG_BUILD_DIR:=$(KERNEL_BUILD_DIR)/wireguard-linux-compat-$(PKG_VERSION)
-PKG_BUILD_PARALLEL:=1
-PKG_USE_MIPS16:=0
-
-# WireGuard's makefile needs this to know where to build the kernel module
-export KERNELDIR:=$(LINUX_DIR)
-
-include $(INCLUDE_DIR)/package.mk
-
-define Package/wireguard/Default
-  SECTION:=net
-  CATEGORY:=Network
-  SUBMENU:=VPN
-  URL:=https://www.wireguard.com
-  MAINTAINER:=Jason A. Donenfeld <Jason@zx2c4.com>
-endef
-
-define Package/wireguard/Default/description
-  WireGuard is a novel VPN that runs inside the Linux Kernel and utilizes
-  state-of-the-art cryptography. It aims to be faster, simpler, leaner, and
-  more useful than IPSec, while avoiding the massive headache. It intends to
-  be considerably more performant than OpenVPN.  WireGuard is designed as a
-  general purpose VPN for running on embedded interfaces and super computers
-  alike, fit for many different circumstances. It uses UDP.
-endef
-
-define Package/wireguard
-  $(call Package/wireguard/Default)
-  TITLE:=WireGuard meta-package
-  DEPENDS:=+wireguard-tools +kmod-wireguard @LINUX_5_4
-endef
-
-include $(INCLUDE_DIR)/kernel-defaults.mk
-include $(INCLUDE_DIR)/package-defaults.mk
-
-define Build/Compile
-	$(MAKE) $(KERNEL_MAKEOPTS) M="$(PKG_BUILD_DIR)/src" modules
-endef
-
-define Package/wireguard/install
-  true
-endef
-
-define Package/wireguard/description
-  $(call Package/wireguard/Default/description)
-endef
-
-define KernelPackage/wireguard
-  SECTION:=kernel
-  CATEGORY:=Kernel modules
-  SUBMENU:=Network Support
-  TITLE:=WireGuard kernel module
-  DEPENDS:=+IPV6:kmod-udptunnel6 +kmod-udptunnel4 @LINUX_5_4
-  FILES:= $(PKG_BUILD_DIR)/src/wireguard.$(LINUX_KMOD_SUFFIX)
-  AUTOLOAD:=$(call AutoProbe,wireguard)
-endef
-
-define KernelPackage/wireguard/description
-  $(call Package/wireguard/Default/description)
-
-  This package provides the kernel module for WireGuard.
-endef
-
-$(eval $(call BuildPackage,wireguard))
-$(eval $(call KernelPackage,wireguard))