MAINTAINERS: Add entry for Qualcomm NAND controller driver

Since I maintain the dt-binding for this controller, I'm stepping
forward to maintain the driver also.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20211004123926.53462-1-manivannan.sadhasivam@linaro.org