MAINTAINERS: add additional ARM BCM281xx/BCM11xxx maintainer

Add myself as an additional maintainer for the Broadcom mobile
SoCs.
Signed-off-by: Matt Porter <mporter@linaro.org>
Acked-by: Christian Daudt <bcm@fixthebug.org>
Signed-off-by: Olof Johansson <olof@lixom.net>

MAINTAINERS

@@ -1860,6 +1860,7 @@ F:	drivers/net/ethernet/broadcom/bnx2x/
 
 BROADCOM BCM281XX/BCM11XXX ARM ARCHITECTURE
 M:	Christian Daudt <bcm@fixthebug.org>
+M:	Matt Porter <mporter@linaro.org>
 L:	bcm-kernel-feedback-list@broadcom.com
 T:	git git://git.github.com/broadcom/bcm11351
 S:	Maintained