kbuild: move KBUILD_LDS, KBUILD_VMLINUX_{OBJS,LIBS} to makefiles.rst

These three variables are not intended to be tweaked by users.
Move them from kbuild.rst to makefiles.rst.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Documentation/kbuild/kbuild.rst

@@ -258,17 +258,3 @@ KBUILD_BUILD_USER, KBUILD_BUILD_HOST
 These two variables allow to override the user@host string displayed during
 boot and in /proc/version. The default value is the output of the commands
 whoami and host, respectively.
-
-KBUILD_LDS
-----------
-The linker script with full path. Assigned by the top-level Makefile.
-
-KBUILD_VMLINUX_OBJS
--------------------
-All object files for vmlinux. They are linked to vmlinux in the same
-order as listed in KBUILD_VMLINUX_OBJS.
-
-KBUILD_VMLINUX_LIBS
--------------------
-All .a "lib" files for vmlinux. KBUILD_VMLINUX_OBJS and KBUILD_VMLINUX_LIBS
-together specify all the object files used to link vmlinux.

Documentation/kbuild/makefiles.rst

@@ -989,6 +989,20 @@ When kbuild executes, the following steps are followed (roughly):
 	top-level Makefile has set any other flags. This provides a
 	means for an architecture to override the defaults.
 
+    KBUILD_LDS
+
+	The linker script with full path. Assigned by the top-level Makefile.
+
+    KBUILD_VMLINUX_OBJS
+
+	All object files for vmlinux. They are linked to vmlinux in the same
+	order as listed in KBUILD_VMLINUX_OBJS.
+
+    KBUILD_VMLINUX_LIBS
+
+	All .a "lib" files for vmlinux. KBUILD_VMLINUX_OBJS and
+	KBUILD_VMLINUX_LIBS together specify all the object files used to
+	link vmlinux.
 
 6.2 Add prerequisites to archheaders
 ------------------------------------