m68knommu: make duplicated ColdFire GPIO init code common for all

The code that adds each ColdFire platforms GPIO signals is duplicated in
each platforms specific code. Remove it from each platforms code and put
a single version in the existing ColdFire gpio subsystem init code.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Acked-by: Steven King <sfking@fdwdc.com>