sh: Add sh7264 device

This is an sh2a device with FPU, video display controller (VDC),
8 serial ports, 3 I2C channels, 2 CAN ports, SD and on-chip USB.

Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>