mt76: depend on kernel 4.14

Do not break the build on kernel 4.9 (ar71xx).

patches/openwrt/0008-mt76-depend-on-kernel-4.14.patch

+From: Matthias Schiffer <mschiffer@universe-factory.net>
+Date: Sat, 14 Jul 2018 01:17:16 +0200
+Subject: mt76: depend on kernel 4.14
+
+Do not break the build on kernel 4.9.
+
+Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
+
+diff --git a/package/kernel/mt76/Makefile b/package/kernel/mt76/Makefile
+index 2906849cf1e43424daa090026123737452dd1a61..e53dcb21515495181959ad1f19cd4d21a4e97e07 100644
+--- a/package/kernel/mt76/Makefile
++++ b/package/kernel/mt76/Makefile
+@@ -23,7 +23,7 @@ include $(INCLUDE_DIR)/package.mk
+ define KernelPackage/mt76-default
+   SUBMENU:=Wireless Drivers
+   DEPENDS:= \
+-	+kmod-mac80211 @PCI_SUPPORT @!LINUX_3_18 \
++	+kmod-mac80211 @PCI_SUPPORT @LINUX_4_14 \
+ 	+@DRIVER_11AC_SUPPORT +@DRIVER_11N_SUPPORT +@DRIVER_11W_SUPPORT
+ endef
+