kbuild: use assignment instead of define ... endef for filechk_* rules

You do not have to use define ... endef for filechk_* rules.

For simple cases, the use of assignment looks cleaner, IMHO.

I updated the usage for scripts/Kbuild.include in case somebody
misunderstands the 'define ... endif' is the requirement.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
diff --git a/Makefile b/Makefile
index 437d603..adf1bd2 100644
--- a/Makefile
+++ b/Makefile
@@ -1041,9 +1041,8 @@
 $(vmlinux-dirs): prepare
 	$(Q)$(MAKE) $(build)=$@ need-builtin=1
 
-define filechk_kernel.release
+filechk_kernel.release = \
 	echo "$(KERNELVERSION)$$($(CONFIG_SHELL) $(srctree)/scripts/setlocalversion $(srctree))"
-endef
 
 # Store (new) KERNELRELEASE string in include/config/kernel.release
 include/config/kernel.release: $(srctree)/Makefile FORCE