MAINTAINERS: move BCM63xx ARM-based SoCs git tree

Update the Broadcom BCM63xx ARM-based SoCs git tree from
github.com/brcm/linux.git to github.com/broadcom/arm-bcm63xx.git where
it now belongs.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>

MAINTAINERS

@@ -2124,7 +2124,7 @@ F:	arch/arm/boot/dts/bcm470*
 BROADCOM BCM63XX ARM ARCHITECTURE
 M:	Florian Fainelli <f.fainelli@gmail.com>
 L:	linux-arm-kernel@lists.infradead.org
-T:	git git://git.github.com/brcm/linux.git
+T:	git git://git.github.com/broadcom/arm-bcm63xx.git
 S:	Maintained
 F:	arch/arm/mach-bcm/bcm63xx.c
 F:	arch/arm/include/debug/bcm63xx.S