mmc: tmio: remove TMIO_MMC_HAVE_CTL_DMA_REG flag

tmio_mmc_host has .enable_dma callback now.
We don't need TMIO_MMC_HAVE_CTL_DMA_REG anymore.
Let's remove it

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>