mmc: mvsdio: delete platform data header

This platform data struct is only used inside the MVSDIO driver,
nowhere else in the entire kernel. Move the struct into the
driver and delete the external header.

Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>