[MIPS] Make SMTC_IDLE_HOOK_DEBUG a proper option in Kconfig.debug.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/kernel/process.c

@@ -51,11 +51,11 @@ ATTRIB_NORET void cpu_idle(void)
 	/* endless idle loop with no priority at all */
 	while (1) {
 		while (!need_resched()) {
-#ifdef CONFIG_MIPS_MT_SMTC
+#ifdef CONFIG_SMTC_IDLE_HOOK_DEBUG
 			extern void smtc_idle_loop_hook(void);
 
 			smtc_idle_loop_hook();
-#endif /* CONFIG_MIPS_MT_SMTC */
+#endif
 			if (cpu_wait)
 				(*cpu_wait)();
 		}