ARM: shmobile: r8a73a4: add I2C controller DT nodes

Add Device Tree nodes for the 9 I2C controllers on r8a73a4, compatible with
the i2c-sh_mobile.c driver.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski+renesas@gmail.com>
Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>