mmc: mark unmaintained drivers

Most of the host controller drivers in the MMC layer lacks an
official maintainer. Make sure this is mentioned in MAINTAINERS
in case someone wants to pick up the ball.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>

MAINTAINERS

@@ -332,6 +332,9 @@ L:	linux-usb-devel@lists.sourceforge.net
 W:	http://www.linux-usb.org/SpeedTouch/
 S:	Maintained
 
+ALCHEMY AU1XX0 MMC DRIVER
+S:	Orphan
+
 ALI1563 I2C DRIVER
 P:	Rudolf Marek
 M:	r.marek@assembler.cz
@@ -649,6 +652,9 @@ L:	linux-atm-general@lists.sourceforge.net (subscribers-only)
 W:	http://linux-atm.sourceforge.net
 S:	Maintained
 
+ATMEL AT91 MCI DRIVER
+S:	Orphan
+
 ATMEL MACB ETHERNET DRIVER
 P:	Haavard Skinnemoen
 M:	hskinnemoen@atmel.com
@@ -2900,6 +2906,9 @@ M:	nico@cam.org
 L:	linux-arm-kernel@lists.arm.linux.org.uk	(subscribers-only)
 S:	Maintained
 
+PXA MMCI DRIVER
+S:	Orphan
+
 QLOGIC QLA2XXX FC-SCSI DRIVER
 P:	Andrew Vasquez
 M:	linux-driver@qlogic.com