m68k: only use local gpio_request_one if not using GPIOLIB

Compiling for targets that use the local gpio code (not GPIOLIB) fail to
compile with:

  CC      arch/m68k/platform/coldfire/device.o
In file included from include/linux/gpio.h:45:0,
                 from arch/m68k/platform/coldfire/device.c:15:
/home/gerg/new-wave.git/linux-3.x/arch/m68k/include/asm/gpio.h:89:19: error: static declaration of ‘gpio_request_one’ follows non-static declaration
include/asm-generic/gpio.h:195:12: note: previous declaration of ‘gpio_request_one’ was here

Fix by conditionally using the local gpio_request_one() function based on
!CONFIG_GPIOLIB.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>