kernel: drop kernel 4.9 support and add 5.4 placeholder

include/kernel-version.mk

@@ -6,13 +6,13 @@ ifdef CONFIG_TESTING_KERNEL
   KERNEL_PATCHVER:=$(KERNEL_TESTING_PATCHVER)
 endif
 
-LINUX_VERSION-4.9 = .223
 LINUX_VERSION-4.14 = .180
 LINUX_VERSION-4.19 = .122
+LINUX_VERSION-5.4 = .40
 
-LINUX_KERNEL_HASH-4.9.223 = cf5300e6f5d8c66c2bed8f00d53f9c58103731809862427012e4010f5d782ae5
 LINUX_KERNEL_HASH-4.14.180 = 444ef973d9b6a6ea174e4a9086f0aea980d8575d13302e431ad688f22e27ed0e
 LINUX_KERNEL_HASH-4.19.122 = 5050268ec5cf003d96366d1611ecfa4ab6974125d6fa26cea1ccb81dd4df00a5
+LINUX_KERNEL_HASH-5.4.40 = 83563f027687ecaafb41d0d2d52056f40ec9822f8a9e43592e215349730020ab
 
 remove_uri_prefix=$(subst git://,,$(subst http://,,$(subst https://,,$(1))))
 sanitize_uri=$(call qstrip,$(subst @,_,$(subst :,_,$(subst .,_,$(subst -,_,$(subst /,_,$(1)))))))

target/linux/ar71xx/Makefile

@@ -13,7 +13,7 @@ FEATURES:=usbgadget
 CPU_TYPE:=24kc
 SUBTARGETS:=generic tiny nand mikrotik
 
-KERNEL_PATCHVER:=4.9
+KERNEL_PATCHVER:=4.14
 
 include $(INCLUDE_DIR)/target.mk