Coverity reports an INTEGER_OVERFLOW issue because ut_asserteq() compares
an unsigned int (mmc_dev_num) with ret, which can hold a negative error
code.
Addresses-Coverity-ID: CID 646439: Integer handling issues (INTEGER_OVERFLOW)
Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>