linux: update to 4.15.4

mk/kernel-ver.mk

@@ -16,10 +16,10 @@ KERNEL_RELEASE:=	1
 KERNEL_VERSION:=	$(ADK_TARGET_KERNEL_GIT_VER)-$(KERNEL_RELEASE)
 endif
 ifeq ($(ADK_TARGET_KERNEL_VERSION_4_15),y)
-KERNEL_FILE_VER:=	4.15
+KERNEL_FILE_VER:=	4.15.4
 KERNEL_RELEASE:=	1
 KERNEL_VERSION:=	$(KERNEL_FILE_VER)-$(KERNEL_RELEASE)
-KERNEL_HASH:=		5a26478906d5005f4f809402e981518d2b8844949199f60c4b6e1f986ca2a769
+KERNEL_HASH:=		a23d7e1a9c1f72528531d9933e59e4cc4556752a2ea029fdc66a1b0fd24c8a3a
 endif
 ifeq ($(ADK_TARGET_KERNEL_VERSION_4_14),y)
 KERNEL_FILE_VER:=	4.14.8

target/config/Config.in.kernelversion

@@ -34,7 +34,7 @@ config ADK_TARGET_KERNEL_VERSION_GIT
 	select ADK_TARGET_KERNEL_IMAGE if ADK_TARGET_SYSTEM_BEAGLEBONE_BLACK
 
 config ADK_TARGET_KERNEL_VERSION_4_15
-	bool "4.15"
+	bool "4.15.4"
 	depends on !ADK_TARGET_ARCH_AVR32
 	depends on !ADK_TARGET_ARCH_CRIS
 	depends on !ADK_TARGET_ARCH_CSKY