package/wireguard-linux-compat: depend on headers < 5.6

Since wireguard is built into kernels 5.6 and later we can't build
wireguard-linux-compat on them, so we need to depend on
!BR2_TOOLCHAIN_HEADERS_AT_LEAST_5_6.

Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/wireguard-linux-compat/Config.in

@@ -3,6 +3,8 @@ config BR2_PACKAGE_WIREGUARD_LINUX_COMPAT
 	depends on BR2_LINUX_KERNEL
 	# kernel module requires 3.10+
 	depends on BR2_TOOLCHAIN_HEADERS_AT_LEAST_3_10
+	# kernel module incompatible with 5.6+
+	depends on !BR2_TOOLCHAIN_HEADERS_AT_LEAST_5_6
 	help
 	  WireGuard is an extremely simple yet fast and modern VPN
 	  that utilizes state-of-the-art cryptography. It aims to be
@@ -20,4 +22,6 @@ config BR2_PACKAGE_WIREGUARD_LINUX_COMPAT
 	  https://www.wireguard.com
 
 comment "wireguard-linux-compat needs a toolchain w/ headers >= 3.10"
-	depends on BR2_LINUX_KERNEL && !BR2_TOOLCHAIN_HEADERS_AT_LEAST_3_10
+	depends on BR2_LINUX_KERNEL
+	depends on !BR2_TOOLCHAIN_HEADERS_AT_LEAST_5_6
+	depends on !BR2_TOOLCHAIN_HEADERS_AT_LEAST_3_10