ARM: shmobile: r8a73a4: Add pin control device to device tree

Add a pfc node to the r8a73a4 device tree.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
[g.liakhovetski+renesas@gmail.com use 2 nodes for address and size]
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski+renesas@gmail.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>