mmc: dw_mmc: fix the spamming log message

When there is no Card which is set to "broken-cd", it's displayed a clock
information continuously. Because it's polling for detecting card.
This patch is fixed this problem.

Fixes: 65257a0d ("mmc: dw_mmc: remove UBSAN warning in dw_mci_setup_bus()")
Reported-by: Tobias Jakobi <tjakobi@math.uni-bielefeld.de>
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>