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

arch/microblaze/Kconfig

 config MICROBLAZE
 	def_bool y
+	select ARCH_NO_SWAP
 	select ARCH_HAS_GCOV_PROFILE_ALL
 	select ARCH_MIGHT_HAVE_PC_PARPORT
 	select ARCH_NO_COHERENT_DMA_MMAP if !MMU
@@ -52,9 +53,6 @@ config CPU_LITTLE_ENDIAN
 
 endchoice
 
-config SWAP
-	def_bool n
-
 config RWSEM_GENERIC_SPINLOCK
 	def_bool y
 

arch/nios2/Kconfig

 # SPDX-License-Identifier: GPL-2.0
 config NIOS2
 	def_bool y
+	select ARCH_NO_SWAP
 	select TIMER_OF
 	select GENERIC_ATOMIC64
 	select GENERIC_CLOCKEVENTS
@@ -38,9 +39,6 @@ config HAS_DMA
 config FPU
 	def_bool n
 
-config SWAP
-	def_bool n
-
 config RWSEM_GENERIC_SPINLOCK
 	def_bool y
 

init/Kconfig

@@ -218,9 +218,16 @@ config DEFAULT_HOSTNAME
 	  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