phy-rcar-usb: add R8A7778 support

The driver currently only supports R8A7779 SoC. Compared to it, R8A7778 USB-PHY
has extra register range containing two high-speed signal quality characteristic
control registers which should be set up  during USB-PHY  startup depending on
whether a ferrite bead is in use or not.  So, we now handle an optional second
memory range in the driver's probe method, add the 'ferrite_bead' field to the
driver's platform data, and add an extra (optional) step to the USB-PHY startup
routine which sets up the extended registers.

Also mark in the driver's Kconfig section  that R8A7778 is now supported and
generally clarify that section, uppercasing the word "phy" and also changing
the module name that got lost in the big driver rename, while at it...

The patch has been tested on the Marzen and BOCK-W boards.

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>