MAINTAINERS: replace an AT91 maintainer

As some help is needed from an active maintainer, replace Andrew Victor
by Alexandre Belloni in the ARM/Atmel MAINTAINERS' entry (aka AT91).
Add an entry to the CREDITS file.

Thanks Andrew for the great role you played during the early days of this
product family.
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Andrew Victor <linux@maxim.org.za>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

CREDITS

@@ -3709,6 +3709,13 @@ N: Dirk Verworner
 D: Co-author of German book ``Linux-Kernel-Programmierung''
 D: Co-founder of Berlin Linux User Group
 
+N: Andrew Victor
+E: linux@maxim.org.za
+W: http://maxim.org.za/at91_26.html
+D: First maintainer of Atmel ARM-based SoC, aka AT91
+D: Introduced support for at91rm9200, the first chip of AT91 family
+S: South Africa
+
 N: Riku Voipio
 E: riku.voipio@iki.fi
 D: Author of PCA9532 LED and Fintek f75375s hwmon driver

MAINTAINERS

@@ -892,11 +892,10 @@ S:	Maintained
 F:	arch/arm/mach-alpine/
 
 ARM/ATMEL AT91RM9200 AND AT91SAM ARM ARCHITECTURES
-M:	Andrew Victor <linux@maxim.org.za>
 M:	Nicolas Ferre <nicolas.ferre@atmel.com>
+M:	Alexandre Belloni <alexandre.belloni@free-electrons.com>
 M:	Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
-W:	http://maxim.org.za/at91_26.html
 W:	http://www.linux4sam.org
 S:	Supported
 F:	arch/arm/mach-at91/