wireguard-tools: remove unnecessary .mk includes

Including kernel.mk moves the package build folder in the linux one, which
is confusing since this isn't building any kernel modules.

package-defaults.mk is already included my package.mk.

Signed-off-by: Andre Heider <[email protected]>

package/network/utils/wireguard-tools/Makefile

@@ -7,7 +7,6 @@
 # See /LICENSE for more information.
 
 include $(TOPDIR)/rules.mk
-include $(INCLUDE_DIR)/kernel.mk
 
 PKG_NAME:=wireguard-tools
 
@@ -24,7 +23,6 @@ PKG_LICENSE_FILES:=COPYING
 PKG_BUILD_PARALLEL:=1
 
 include $(INCLUDE_DIR)/package.mk
-include $(INCLUDE_DIR)/package-defaults.mk
 
 MAKE_PATH:=src
 MAKE_VARS += PLATFORM=linux