mmc: uniphier-sd: Add support for 64bit controller

mmc: uniphier-sd: Add support for 64bit controller

The Renesas RCar Gen3 contains the same controller, originally
Matsushita, yet the register addresses are shifted by 1 to the
left. The whole controller is also 64bit, including the data
FIFOs and RSP registers. This patch adds support for handling
the register IO by shifting the register offset by 1 in the IO
accessor functions.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Jaehoon Chung <jh80.chung@samsung.com>