mmc: mmc_get_op_cond: Allow quiet detection of eMMC

mmc: mmc_get_op_cond: Allow quiet detection of eMMC

Add a new 'quiet' argument to mmc_get_op_cond() function which avoids
printing error message when SD/eMMC card is not detected.

Espressobin and mx6cuboxi boards use this function for detecting presence
of eMMC and therefore it is expected and normal that eMMC does not have to
be connected. So error message "Card did not respond to voltage select!"
should be skipped in this case as it is not an error.

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Stefan Roese <sr@denx.de>
Acked-by: Jaehoon Chung <jh80.chung@samsung.com>