sh: Make memory hot-add and hot-remove depend on MMU.

Cleans up link numerous build issues with page migration and so on when
enabled on nommu builds.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

arch/sh/mm/Kconfig

@@ -132,11 +132,11 @@ config ARCH_SELECT_MEMORY_MODEL
 
 config ARCH_ENABLE_MEMORY_HOTPLUG
 	def_bool y
-	depends on SPARSEMEM
+	depends on SPARSEMEM && MMU
 
 config ARCH_ENABLE_MEMORY_HOTREMOVE
 	def_bool y
-	depends on SPARSEMEM
+	depends on SPARSEMEM && MMU
 
 config ARCH_MEMORY_PROBE
 	def_bool y