arch: add Kconfig for stack growth direction

This was previously just a #define in one header file, but we need
this expressed in Kconfig space in case some feature only works
properly with downward-growing stacks.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>

arch/Kconfig

@@ -88,6 +88,13 @@ config PRIVILEGED_STACK_SIZE
 	  this region will be inaccessible from user mode.  During system calls,
 	  this region will be utilized by the system call.
 
+config STACK_GROWS_UP
+	bool "Stack grows towards higher memory addresses"
+	default n
+	help
+	  Select this option if the architecture has upward growing thread
+	  stacks. This is not common.
+
 config MAX_THREAD_BYTES
 	int "Bytes to use when tracking object thread permissions"
 	default 2

include/misc/stack.h

@@ -33,7 +33,7 @@ static inline size_t stack_unused_space_get(const char *stack, size_t size)
 	 * (or configurable direction) is added this check should be confirmed
 	 * that correct Kconfig option is used.
 	 */
-#if defined(STACK_GROWS_UP)
+#if defined(CONFIG_STACK_GROWS_UP)
 	for (i = size - 1; i >= 0; i--) {
 		if ((unsigned char)stack[i] == 0xaa) {
 			unused++;