mmc: sdhci-of-esdhc: set proper dma mask for ls104x chips

SDHCI controller in ls1043a and ls1046a generate 40-bit wide addresses
when doing DMA. Make sure that the corresponding dma mask is correctly
configured.

Context: when enabling smmu on these chips the following problem is
encountered: the smmu input address size is 48 bits so the dma mappings
for sdhci end up 48-bit wide. However, on these chips sdhci only use
40-bits of that address size when doing dma.
So you end up with a 48-bit address translation in smmu but the device
generates transactions with clipped 40-bit addresses, thus smmu context
faults are triggered. Setting up the correct dma mask fixes this
situation.

Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>