ARM: shmobile: emev2: Remove legacy machine_desc.map_io() callback

Commit FIXME ("ARM: shmobile: Consolidate SCU mapping code") removed the
last user of the static mapping on emev2-based systems.  Remove the
mapping and the legacy machine_desc.map_io() callback.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>