mmc: mvsdio: silence card detect notice

mvsdio reports method of card detection with dev_notice, while for
removable cards it may be sane, for non-removable cards it is not.
Also, as the user cannot do anything about it, silence the message
by reducing it from dev_notice to dev_dbg.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Acked-by: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Chris Ball <chris@printf.net>