s3cmci: change GPIO to gpiolib from S3C24XX specific calls

Move to using gpiolib to access the card detect and write protect GPIO
lines instead of using the platform speicifc s3c2410_gpio calls.

Also ensure that the card lines are claimed the same way to avoid overlap
with any other drivers.

Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>