mmc: mmci_sdmmc: fix DMA API warning max segment size

Turning on CONFIG_DMA_API_DEBUG_SG results in the following warning:
WARNING: CPU: 1 PID: 85 at kernel/dma/debug.c:1302
debug_dma_map_sg+0x2a0/0x3cc mmci-pl18x 58005000.sdmmc: DMA-API: mapping sg
segment longer than device claims to support [len=126976] [max=65536]

dma api debug checks and compares the segment size to dma_get_max_seg_size
(dev->dma_parms->max_segment_size), the sdmmc variant has an internal DMA
and should define its max_segment_size constraint to avoid this warning.

This Patch defines the dev->dma_parms->max_segment_size with the constraint
already set for mmc core (host->mmc->max_seg_size).

Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
Link: https://lore.kernel.org/r/20200526155103.12514-3-ludovic.barre@st.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>