kbuild: remove redundant clean-files from scripts/kconfig/Makefile

Now mconf, qconf, gconf, nconf are always added to hostprogs-y.
Files added to hostprogs-y are removed by "make clean".
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>

scripts/kconfig/Makefile

@@ -161,7 +161,6 @@ hostprogs-y := conf nconf mconf kxgettext qconf gconf
 
 clean-files	:= qconf.moc .tmp_qtcheck .tmp_gtkcheck
 clean-files	+= zconf.tab.c zconf.lex.c zconf.hash.c gconf.glade.h
-clean-files     += mconf qconf gconf nconf
 clean-files     += config.pot linux.pot
 
 # Check that we have the required ncurses stuff installed for lxdialog (menuconfig)