kconfig: generate lexer and parser during build instead of shipping

zconf.lex.c is generated by flex, zconf.tab.c by bison.  Instead of
running flex and bison during the kernel building, we conventionally
version-control those artifacts with _shipped suffix.

It is tedious to manually regenerate them every time we change the
real sources, zconf.l and zconf.y.

Remove the _shipped files and switch over to build-time generation
of the intermediate C files.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

scripts/kconfig/Makefile

@@ -191,6 +191,7 @@ gconf-objs	:= gconf.o zconf.tab.o
 
 hostprogs-y := conf nconf mconf kxgettext qconf gconf
 
+targets		+= zconf.tab.c zconf.lex.c
 clean-files	:= qconf.moc .tmp_qtcheck .tmp_gtkcheck
 clean-files	+= zconf.tab.c zconf.lex.c gconf.glade.h
 clean-files     += config.pot linux.pot