MAINTAINERS: Add memory drivers to AT91 entry

Both atmel-ebi and atmel-sdram are maintained as part of the Atmel ARM
SoCs.

Suggested-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
diff --git a/MAINTAINERS b/MAINTAINERS
index e5ae923..18e9fa8 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1110,6 +1110,7 @@
 F:	arch/arm/boot/dts/sama*.dts
 F:	arch/arm/boot/dts/sama*.dtsi
 F:	arch/arm/include/debug/at91.S
+F:	drivers/memory/atmel*
 
 ARM/ATMEL AT91 Clock Support
 M:	Boris Brezillon <boris.brezillon@free-electrons.com>