kbuild: Remove scripts/elfconfig.h with "make clean"

We have a bit of a mess with build-targets, EXTRA_TARGETS, targets,
which needs cleaning up some time. Anyway, we just add $(targets) to the
files which get deleted with "make clean" for now.

scripts/Makefile

@@ -5,7 +5,7 @@
 # fix-dep: 	 Used to generate dependency information during build process
 # split-include: Divide all config symbols up in a number of files in
 #                include/config/...
-# docproc: 	 Preprocess .tmpl file in order to generate .sgml documentation
+# docproc: 	 Preprocess .tmpl file in order to generate .sgml docs
 # conmakehash:	 Create arrays for initializing the kernel console tables
 
 host-progs    := fixdep split-include conmakehash docproc kallsyms modpost \

scripts/Makefile.clean

@@ -35,7 +35,7 @@ subdir-ymn	:= $(addprefix $(obj)/,$(subdir-ymn))
 
 # ==========================================================================
 
-__clean-files := $(wildcard $(EXTRA_TARGETS) $(host-progs) $(clean-files))
+__clean-files := $(wildcard $(EXTRA_TARGETS) $(host-progs) $(clean-files) $(targets))
 
 quiet_cmd_clean = CLEAN   $(obj)
       cmd_clean = rm -f $(__clean-files); $(clean-rule)