ARM: shmobile: r7s72100: Switch to new style MTU2 device

The MTU2 (Multi-Function Timer Pulse Unit 2) 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>
Tested-by: Wolfram Sang <wsa@sang-engineering.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>