kconfig: remove duplicate SWAP symbol defintions

microblaze and nios2 define their own always n SWAP symbols.  Remove those
and let the generic defintion do the right thing by adding a new symbol
to disable swap entirely.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/init/Kconfig b/init/Kconfig
index 041f3a0..1e69f93 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -218,9 +218,16 @@
 	  but you may wish to use a different default here to make a minimal
 	  system more usable with less configuration.
 
+#
+# For some reason microblaze and nios2 hard code SWAP=n.  Hopefully we can
+# add proper SWAP support to them, in which case this can be remove.
+#
+config ARCH_NO_SWAP
+	bool
+
 config SWAP
 	bool "Support for paging of anonymous memory (swap)"
-	depends on MMU && BLOCK
+	depends on MMU && BLOCK && !ARCH_NO_SWAP
 	default y
 	help
 	  This option allows you to choose whether you want to have support