kernel: copy kernel 4.19 code to 5.4

No changes were done to the patches while coping them. Currently they do
not apply on top of kernel 5.4.

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

target/linux/generic/backport-5.4/011-kbuild-export-SUBARCH.patch

@@ -0,0 +1,23 @@
+From 173019b66dcc9d68ad9333aa744dad1e369b5aa8 Mon Sep 17 00:00:00 2001
+From: Felix Fietkau <nbd@nbd.name>
+Date: Sun, 9 Jul 2017 00:26:53 +0200
+Subject: [PATCH 34/34] kernel: add compile fix for linux 4.9 on x86
+
+Signed-off-by: Felix Fietkau <nbd@nbd.name>
+---
+ Makefile | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+--- a/Makefile
++++ b/Makefile
+@@ -432,8 +432,8 @@ KBUILD_LDFLAGS :=
+ GCC_PLUGINS_CFLAGS :=
+ CLANG_FLAGS :=
+ 
+-export ARCH SRCARCH CONFIG_SHELL HOSTCC KBUILD_HOSTCFLAGS CROSS_COMPILE AS LD CC
+-export CPP AR NM STRIP OBJCOPY OBJDUMP KBUILD_HOSTLDFLAGS KBUILD_HOSTLDLIBS
++export ARCH SRCARCH SUBARCH CONFIG_SHELL HOSTCC KBUILD_HOSTCFLAGS CROSS_COMPILE AS LD
++export CC CPP AR NM STRIP OBJCOPY OBJDUMP KBUILD_HOSTLDFLAGS KBUILD_HOSTLDLIBS
+ export MAKE LEX YACC AWK GENKSYMS INSTALLKERNEL PERL PYTHON PYTHON2 PYTHON3 UTS_MACHINE
+ export HOSTCXX KBUILD_HOSTCXXFLAGS LDFLAGS_MODULE CHECK CHECKFLAGS
+