soc: x86/atom: imply mmu, do not select it

Board should be able to deselect mmu, so imply instead of strict
selection.

userspace is selected for atom already on the CPU level, so do not
reselect.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>

soc/intel/atom/Kconfig

@@ -3,6 +3,5 @@
 config SOC_ATOM
 	select X86
 	select CPU_ATOM
-	select X86_MMU
-	select ARCH_HAS_USERSPACE
+	imply X86_MMU
 	select ARCH_HAS_RESERVED_PAGE_FRAMES

subsys/testsuite/Kconfig

@@ -131,8 +131,8 @@ config TEST_ENABLE_USERSPACE
 	bool
 	depends on TEST_USERSPACE
 	depends on ARCH_HAS_USERSPACE
-	select USERSPACE
-	select DYNAMIC_OBJECTS
+	imply USERSPACE
+	imply DYNAMIC_OBJECTS
 	default y
 	help
 	  This hidden option implements the TEST_USERSPACE logic. It turns on