staging: memrar: remove driver from tree

It's no longer needed at all.

Cc: Ossama Othman <ossama.othman@intel.com>
Cc: Eugene Epshteyn <eugene.epshteyn@intel.com>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>