m68k: move coldfire platform code

Move the m68k ColdFire platform support code directory to be with the
existing m68k platforms. Although the ColdFire is not a platform as such,
we have always kept all its support together. No reason to change that
as this time.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>