m68k: pull mach_beep in setup.c

It is possible to select INPUT_M68K_BEEP in a nommu configuration. This
results in the following link error:

drivers/input/misc/m68kspkr.o: In function `m68kspkr_event':
m68kspkr.c:(.text+0x3a): undefined reference to `mach_beep'
m68kspkr.c:(.text+0x5e): undefined reference to `mach_beep'
m68kspkr.c:(.text+0x78): undefined reference to `mach_beep'
drivers/input/misc/m68kspkr.o: In function `m68kspkr_init':
m68kspkr.c:(.init.text+0x4): undefined reference to `mach_beep'

Pull the mach_beep definition in setup.c to avoid it.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>