MAINTAINERS: add at91 usart spi driver

Added entry for at91 usart mfd driver.

Signed-off-by: Radu Pirea <radu.pirea@microchip.com>

Author: Radu Pirea

MAINTAINERS

@@ -8038,6 +8038,13 @@ F:	drivers/mfd/at91-usart.c
 F:	include/dt-bindings/mfd/at91-usart.h
 F:	Documentation/devicetree/bindings/mfd/atmel-usart.txt
 
+MICROCHIP AT91 USART SPI DRIVER
+M:	Radu Pirea <radu.pirea@microchip.com>
+L:	linux-spi@vger.kernel.org
+S:	Supported
+F:	drivers/spi/spi-at91-usart.c
+F:	Documentation/devicetree/bindings/mfd/atmel-usart.txt
+
 MICROCHIP KSZ SERIES ETHERNET SWITCH DRIVER
 M:	Woojung Huh <Woojung.Huh@microchip.com>
 M:	Microchip Linux Driver Support <UNGLinuxDriver@microchip.com>