mmc: tmio: Clamp SD_SECCNT to 16bit values on 16bit IP

mmc: tmio: Clamp SD_SECCNT to 16bit values on 16bit IP

On 16bit variants of the TMIO SD IP, the SECCNT register can only be
programmed to 16bit values, while on the 32bit and 64bit variants it
can be programmed to 32bit values. The SECCNT register indicates the
maximum number of blocks in a continuous transfer. Hence, limit the
maximum continuous transfer block count to 65535 blocks on 16bit
variants of the TMIO IP and to BIT(32)-1 blocks on 32bit and 64bit
variants.

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