subsys/debug: Stub out debug thread info for RX arch

This architecture is missing lots of support bits. Stub out this piece so
we can get more things building.

Signed-off-by: Keith Packard <keithp@keithp.com>

Author: keith-packard

subsys/debug/thread_info.c

@@ -92,6 +92,9 @@ const size_t _kernel_thread_info_offsets[] = {
 	 * unimplemented to avoid the #warning below.
 	 */
 	[THREAD_INFO_OFFSET_T_STACK_PTR] = THREAD_INFO_UNIMPLEMENTED,
+#elif defined(CONFIG_RX)
+	/* RX doesn't store *anything* inside thread objects yet */
+	[THREAD_INFO_OFFSET_T_STACK_PTR] = THREAD_INFO_UNIMPLEMENTED,
 #else
 	/* Use a special value so that OpenOCD knows that obtaining the stack
 	 * pointer is not possible on this particular architecture.