mmc: dw_mmc: fix 32bit little-endian access of des1 field

The IDMAC_SET_BUFFER1_SIZE() macro modifies des1, but does
not check if the value being passed is big or little endian
desptire the des1 field being marked as __le32.

Fix the issue by ensuring the values are changed from the
cpu endian to the descriptor endian by using cpu_to_le32.

Spotted whilst doing big endian conversion work on Exynos,
and stops the mmc worker thread from stalling.

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Reviewed-by: Shawn Lin <shawn.lin@rock-chips.com>
Tested-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>