Updated MMC/SD Card driver to support hot add and remove of the media (SD Cards)...

Updated MMC/SD Card driver to support hot add and remove of the media (SD Cards) and enable write protect of SD Cards. Had to update pads for WP bit as it was not being programmed as a GPIO. I also changed some of the PAD #defins as there were only really 3 states, so OR things in the table in the .c file did not make a lot of sense.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@10450 6f19259b-4bc3-4df7-8a09-765794883524