mmc: tmio: sdhi: Merge DTCNTL access into single register write

It is perfectly fine to write th DTCNTL TAP count and enable the
SCC sampling clock operation in the same write.

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