sh: cpuidle: Migrate off of hwblk API.

Now that the hwblk API is unused and going away, migrate cpuidle off of
it. This is a pretty straightforward migration given that we weren't
really making use of the allowed mode overloading in the first place, so
simply default to regular sleep mode.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/include/asm/hwblk.h

@@ -49,7 +49,6 @@ struct hwblk_info {
     !defined(CONFIG_CPU_SUBTYPE_SH7724)
 /* Should be defined by processor-specific code */
 int arch_hwblk_init(void);
-int arch_hwblk_sleep_mode(void);
 
 int hwblk_register(struct hwblk_info *info);
 int hwblk_init(void);