kconfig: replace $(UNAME_RELEASE) with function call

Now that 'shell' function is supported, this can be self-contained in
Kconfig.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Ulf Magnusson <ulfalizer@gmail.com>

Makefile

@@ -284,8 +284,7 @@ include scripts/Kbuild.include
 # Read KERNELRELEASE from include/config/kernel.release (if it exists)
 KERNELRELEASE = $(shell cat include/config/kernel.release 2> /dev/null)
 KERNELVERSION = $(VERSION)$(if $(PATCHLEVEL),.$(PATCHLEVEL)$(if $(SUBLEVEL),.$(SUBLEVEL)))$(EXTRAVERSION)
-UNAME_RELEASE := $(shell uname --release)
-export VERSION PATCHLEVEL SUBLEVEL KERNELRELEASE KERNELVERSION UNAME_RELEASE
+export VERSION PATCHLEVEL SUBLEVEL KERNELRELEASE KERNELVERSION
 
 # SUBARCH tells the usermode build what the underlying arch is.  That is set
 # first, and if a usermode build is happening, the "ARCH=um" on the command

init/Kconfig

@@ -2,9 +2,9 @@ config DEFCONFIG_LIST
 	string
 	depends on !UML
 	option defconfig_list
-	default "/lib/modules/$(UNAME_RELEASE)/.config"
+	default "/lib/modules/$(shell,uname --release)/.config"
 	default "/etc/kernel-config"
-	default "/boot/config-$(UNAME_RELEASE)"
+	default "/boot/config-$(shell,uname --release)"
 	default ARCH_DEFCONFIG
 	default "arch/$(ARCH)/defconfig"