patches/openwrt: dvb: add support for backported TDA18250

This tuner is used for Xbox One Digital TV Tuner. It was added in kernel
4.16. I added clear comment, where it starts and where it ends to be sure
  that those comments can be removed as OpenWrt in their master branch
wants to have kernel 5.4, otherwise it should be there at least for
OpenWrt 19.07. Otherwise the kernel config won't be recognized.

patches/openwrt/to-upstream/0009-dvb-add-support-for-TDA18250-tuner.patch

+From a429736c56af069b6511d623679f2bb1939515b4 Mon Sep 17 00:00:00 2001
+From: Josef Schlehofer <pepe.schlehofer@gmail.com>
+Date: Thu, 2 Apr 2020 16:05:45 +0200
+Subject: [PATCH] dvb: add support for TDA18250 tuner
+
+---
+ package/kernel/linux/modules/dvb.mk | 16 ++++++++++++++++
+ 1 file changed, 16 insertions(+)
+
+diff --git a/package/kernel/linux/modules/dvb.mk b/package/kernel/linux/modules/dvb.mk
+index 3db464e10e..4f8e7df3e1 100644
+--- a/package/kernel/linux/modules/dvb.mk
++++ b/package/kernel/linux/modules/dvb.mk
+@@ -807,6 +807,22 @@ define MediaTuner
+   AUTOLOAD:=$(call AutoProbe,$1)
+ endef
+ 
++## START: Added in kernel 4.16
++
++define KernelPackage/media-tuner-tda18250
++  TITLE:=NXP TDA18250 silicon tuner
++  $(call MediaTuner,tda18250,CONFIG_MEDIA_TUNER_TDA18250)
++  DEPENDS+=+kmod-regmap-i2c +kmod-video-core
++endef
++
++define KernelPackage/media-tuner-tda18250/description
++ NXP TDA18250 silicon tuner driver.
++endef
++
++$(eval $(call KernelPackage,media-tuner-tda18250))
++
++## End: Added in kernel 4.16
++
+ define KernelPackage/media-tuner-e4000
+   TITLE:=Elonics E4000 silicon tuner
+   $(call MediaTuner,e4000,CONFIG_MEDIA_TUNER_E4000)
+-- 
+2.26.0
+