m68k: change m68knommu maintainer email address

Change my email address in the "UCLINUX (M68KNOMMU and COLDFIRE)" entry
from gerg@uclinux.org to gerg@linux-m68k.org. I intend using that for
m68k (and uclinux) specific work from now on.

Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>