mmc: block: Suppress empty whitespaces in prints

If the device is not read-only, then we will be printing an empty
whitespace before the newline, fix that.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20230509194455.1791890-1-f.fainelli@gmail.com


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