On some Samsung SoCs not all SDHCI controllers have card detect (CD)
line. For some embedded designs it is not even needed, because ususally
the device (like SDIO flash memory or wifi controller) is permanently
wired to the controller. There are also systems which have a card detect
line connected to some of the external interrupt lines or the presence
of the card depends on some other actions (like enabling a power
regulator).

This patch adds all required changes to platform support code, so
another patch, which extends the driver with support for the new card
detection methods can be applied.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
[kgene.kim@samsung.com: minor title and coding-style fixes]
[kgene.kim@samsung.com: fix build errors]
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>