mmc: dw_mmc-hi3798cv200: Remove unneeded assignment

The err is being set to 0 and replaced every time after this
assignment. Remove this assignment as it is extraneous.

Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Link: https://lore.kernel.org/r/20240307145013.2721326-1-usama.anjum@collabora.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>