mmc: Enable Ricoh MMC quirk by default

Config option MMC_RICOH_MMC's help text reads:

	  If unsure, say Y.

However the option defaults to N. Set the default to Y to match the
recommendation in the help text.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Cc: Chris Ball <chris@printf.net>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Philipl Langdale <philipl@overt.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>