sh: dreamcast: rtc: push down rtc class ops into driver

The SH RTC support has an extra level of indirection to provide
either the old read_persistent_clock/update_persistent_clock
interface or the rtc-generic device for hctosys/systohc.

Both do the same thing for dreamcast, so we can do away with the
abstraction and simply let the RTC core code to take care of it.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/sh/include/mach-dreamcast/mach/sysasic.h

@@ -42,7 +42,6 @@
 /* arch/sh/boards/mach-dreamcast/irq.c */
 extern int systemasic_irq_demux(int);
 extern void systemasic_irq_init(void);
-extern void aica_time_init(void);
 
 #endif /* __ASM_SH_DREAMCAST_SYSASIC_H */