[POWERPC] devres: Add devm_ioremap_prot()

We provide an ioremap_flags, so this provides a corresponding
devm_ioremap_prot.  The slight name difference is at Ben
Herrenschmidt's request as he plans on changing ioremap_flags to
ioremap_prot in the future.

Signed-off-by: Emil Medve <Emilian.Medve@Freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Acked-by: Tejun Heo <htejun@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>