kernel: generic: Add kernel 4.14 support

This adds initial support for kernel 4.14 based on the patches for
kernel 4.9.

In the configuration I deactivated some of the new possible security
features like:
CONFIG_REFCOUNT_FULL
CONFIG_SLAB_FREELIST_HARDENED
CONFIG_SOFTLOCKUP_DETECTOR
CONFIG_WARN_ALL_UNSEEDED_RANDOM

And these overlay FS options are also deactivated:
CONFIG_OVERLAY_FS_INDEX
CONFIG_OVERLAY_FS_REDIRECT_DIR

I activated this:
CONFIG_FORTIFY_SOURCE
CONFIG_POSIX_TIMERS
CONFIG_SLAB_MERGE_DEFAULT
CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED

I am not sure if I did the porting correct for the following patches:
target/linux/generic/backport-4.14/020-backport_netfilter_rtcache.patch
target/linux/generic/hack-4.14/220-gc_sections.patch
target/linux/generic/hack-4.14/321-powerpc_crtsavres_prereq.patch
target/linux/generic/pending-4.14/305-mips_module_reloc.patch
target/linux/generic/pending-4.14/611-netfilter_match_bypass_default_table.patch
target/linux/generic/pending-4.14/680-NET-skip-GRO-for-foreign-MAC-addresses.patch

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

target/linux/generic/hack-4.14/207-disable-modorder.patch

@@ -0,0 +1,44 @@
+From c9ef4ab0f54356ee9f91d9676ea0ec123840ddc7 Mon Sep 17 00:00:00 2001
+From: Felix Fietkau <nbd@nbd.name>
+Date: Fri, 7 Jul 2017 16:57:33 +0200
+Subject: kernel: do not build modules.order
+
+It is not needed for anything on the system and skipping this saves some
+build time, especially in cases where there is nothing to do.
+
+lede-commit: afc1675833a7bf5df094f59f7250369520646d04
+Signed-off-by: Felix Fietkau <nbd@nbd.name>
+---
+ Makefile               | 2 --
+ scripts/Makefile.build | 2 +-
+ 2 files changed, 1 insertion(+), 3 deletions(-)
+
+--- a/Makefile
++++ b/Makefile
+@@ -1208,7 +1208,6 @@ all: modules
+ 
+ PHONY += modules
+ modules: $(vmlinux-dirs) $(if $(KBUILD_BUILTIN),vmlinux) modules.builtin
+-	$(Q)$(AWK) '!x[$$0]++' $(vmlinux-dirs:%=$(objtree)/%/modules.order) > $(objtree)/modules.order
+ 	@$(kecho) '  Building modules, stage 2.';
+ 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
+ 
+@@ -1237,7 +1236,6 @@ _modinst_:
+ 		rm -f $(MODLIB)/build ; \
+ 		ln -s $(CURDIR) $(MODLIB)/build ; \
+ 	fi
+-	@cp -f $(objtree)/modules.order $(MODLIB)/
+ 	@cp -f $(objtree)/modules.builtin $(MODLIB)/
+ 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modinst
+ 
+--- a/scripts/Makefile.build
++++ b/scripts/Makefile.build
+@@ -94,7 +94,7 @@ modorder-target := $(obj)/modules.order
+ # We keep a list of all modules in $(MODVERDIR)
+ 
+ __build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \
+-	 $(if $(KBUILD_MODULES),$(obj-m) $(modorder-target)) \
++	 $(if $(KBUILD_MODULES),$(obj-m)) \
+ 	 $(subdir-ym) $(always)
+ 	@:
+