mmc-utils: Add arg argument to set_single_cmd

Will prove itself useful in a minute.
No functional change.

Signed-off-by: Avri Altman <avri.altman@wdc.com>
Link: https://lore.kernel.org/r/20230625103814.105-3-avri.altman@wdc.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
1 file changed