m68k: Remove unused set_clock_mmss() helpers

Commit 397ac99c6c ("m68k: remove dead timer code") removed set_rtc_mmss()
because it was unused in 2012. However, this was itself the only user of the
mach_set_clock_mmss() callback and the many implementations of that callback,
which are equally unused.

This removes all of those as well.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Greg Ungerer <gerg@linux-m68k.org>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

arch/m68k/kernel/setup_no.c

@@ -51,7 +51,6 @@ char __initdata command_line[COMMAND_LINE_SIZE];
 
 /* machine dependent timer functions */
 void (*mach_sched_init)(irq_handler_t handler) __initdata = NULL;
-int (*mach_set_clock_mmss)(unsigned long);
 int (*mach_hwclk) (int, struct rtc_time*);
 
 /* machine dependent reboot functions */