kbuild: get rid of kernel/ prefix from in-tree modules.{order,builtin}

Removing the 'kernel/' prefix will make our life easier because we can
simply do 'cat modules.order' to get all built modules with full paths.

Currently, we parse the first line of '*.mod' files in $(MODVERDIR).
Since we have duplicated functionality here, I plan to remove MODVERDIR
entirely.

In fact, modules.order is generated also for external modules in a
broken format. It adds the 'kernel/' prefix to the absolute path of
the module, like this:

  kernel//path/to/your/external/module/foo.ko

This is fine for now since modules.order is not used for external
modules. However, I want to sanitize the format everywhere towards
the goal of removing MODVERDIR.

We cannot change the format of installed module.{order,builtin}.
So, 'make modules_install' will add the 'kernel/' prefix while copying
them to $(MODLIB)/.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/scripts/modules-check.sh b/scripts/modules-check.sh
index 39e8cb3..f51f446 100755
--- a/scripts/modules-check.sh
+++ b/scripts/modules-check.sh
@@ -9,7 +9,7 @@
 	for m in $(sed 's:.*/::' modules.order | sort | uniq -d)
 	do
 		echo "warning: same module names found:" >&2
-		sed -n "/\/$m/s:^kernel/:  :p" modules.order >&2
+		sed -n "/\/$m/s:^:  :p" modules.order >&2
 	done
 }