ARM: S3C64XX: Tone down SDHCI debugging

The MMC core calls s3c6400_setup_sdhcp_cfg_card() very frequently, causing
the log message in there at KERN_INFO to be displayed a lot which is slow
and overly chatty. Convert the message into a pr_debug() to tone this down.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>