MAINTAINERS: Remove Piotr Sroka and mark Cadence NFC as orphaned

Piotr's address is bouncing, remove him from MAINTAINERS and mark the
driver he was maintaining, Cadence's, as orphaned.
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20200510211809.15610-1-miquel.raynal@bootlin.com

MAINTAINERS

@@ -3741,9 +3741,8 @@ F:	Documentation/devicetree/bindings/media/cdns,*.txt
 F:	drivers/media/platform/cadence/cdns-csi2*
 
 CADENCE NAND DRIVER
-M:	Piotr Sroka <piotrs@cadence.com>
 L:	linux-mtd@lists.infradead.org
-S:	Maintained
+S:	Orphan
 F:	Documentation/devicetree/bindings/mtd/cadence-nand-controller.txt
 F:	drivers/mtd/nand/raw/cadence-nand-controller.c