usb: renesas_usbhs: add R-Car Gen. 2 init and power control

In preparation for DT conversion to reduce reliance on platform device
callbacks.

Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
(cherry picked from commit 8ecef00fe1f33658ee36e902dba6850b51312073)
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
6 files changed