Omap35xxPkg/MMCHSDxe: Fixed initialization when started from gBS->ConnectController()

Omap35xxPkg/MMCHSDxe: Fixed initialization when started from gBS->ConnectController()

As soon as the MMCHSDxe is initialized is reinstalled its protocol.
It was crashing when the PartitionDxe was scanning for partition headers and the the MMC driver
reinstalls its protocols in the same time. The initial DiskIo and BlockIo instances used
by PartitionDxe were not valid after this reinstallation.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@12160 6f19259b-4bc3-4df7-8a09-765794883524