[ARM] mm 10: allow memory type to be specified with ioremap

__ioremap() took a set of page table flags (specifically the cacheable
and bufferable bits) to control the mapping type.  However, with
the advent of ARMv6, this is far too limited.

Replace the page table flags with a memory type index, so that the
desired attributes can be selected from the mem_type table.

Finally, to prevent silent miscompilation due to the differing
arguments, rename the __ioremap() and __ioremap_pfn() functions.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>