mmc: tmio: merge distributed include files

There is no reason to have a public and private header file. Merge them
into a private one, so looking up symbols is less confusing.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>