Fix build problem after Kconfig file change

conf --silentoldconfig generates required autoconf.h file
but when invoked on modified Kconfig it will ask for user
input which breaks the build. To automatically regenerate
config structure and then autogenerate headers run
config --olddefconfig first.
Signed-off-by: NZbigniew Bodek <zbigniew.bodek@huawei.com>
Change-Id: If7f7653c80cc0c5c0d84015b8e50fcb66568d00a

Makefile

@@ -126,6 +126,7 @@ menuconfig:$(MENUCONFIG_PATH)/mconf
 
 genconfig:$(MENUCONFIG_PATH)/conf
 	$(HIDE)mkdir -p include/config include/generated
+	$< --olddefconfig $(KCONFIG_FILE_PATH)
 	$< --silentoldconfig $(KCONFIG_FILE_PATH)
 	-mv -f $(LITEOS_MENUCONFIG_H) $(LITEOS_PLATFORM_MENUCONFIG_H)
 ##### menuconfig end #######