m68k: mm: Change ColdFire pgtable_t

To match what we did to the Motorola MMU routines, change the ColdFire
pgalloc.

The result is that ColdFire and Sun3 pgalloc are actually very similar
and could conceivably be unified.

Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Greg Ungerer <gerg@linux-m68k.org>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Tested-by: Greg Ungerer <gerg@linux-m68k.org>
Link: https://lore.kernel.org/r/20200131125403.995781825@infradead.org


Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>