kconfig: include common Kconfig files from top-level Kconfig

Instead of duplicating the source statements in every architecture just
do it once in the toplevel Kconfig file.

Note that with this the inclusion of arch/$(SRCARCH/Kconfig moves out of
the top-level Kconfig into arch/Kconfig so that don't violate ordering
constraits while keeping a sensible menu structure.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

arch/nds32/Kconfig

@@ -71,8 +71,6 @@ config FIX_EARLYCON_MEM
 config PGTABLE_LEVELS
 	default 2
 
-source "init/Kconfig"
-
 menu "System Type"
 source "arch/nds32/Kconfig.cpu"
 config NR_CPUS
@@ -91,23 +89,9 @@ endmenu
 
 menu "Kernel Features"
 source "kernel/Kconfig.preempt"
-source "kernel/Kconfig.freezer"
-source "mm/Kconfig"
 source "kernel/Kconfig.hz"
 endmenu
 
-menu "Executable file formats"
-source "fs/Kconfig.binfmt"
-endmenu
-
-source "net/Kconfig"
-source "drivers/Kconfig"
-source "fs/Kconfig"
-
 menu "Kernel hacking"
 source "lib/Kconfig.debug"
 endmenu
-
-source "security/Kconfig"
-source "crypto/Kconfig"
-source "lib/Kconfig"