ARM: shmobile: r8a7740: Switch to new style TMU device

The TMU (Timer Unit) driver implements a new style of platform data that
handles the timer as a single device with multiple channel. Switch from
the old-style platform data to the new-style platform data.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>