MAINTAINERS: Explicitly add linux-arm-kernel for bcm2835

get_maintainers.pl would list linux-arm-kernel for most bcm2835
changes because it's under arch/arm, but might not for other bcm2835
drivers.  Most ARM architectures appear to list linux-arm-kernel as an
appropriate list as well.
Signed-off-by: Eric Anholt <eric@anholt.net>
Suggested-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>

MAINTAINERS

@@ -2218,6 +2218,7 @@ M:	Stephen Warren <swarren@wwwdotorg.org>
 M:	Lee Jones <lee@kernel.org>
 M:	Eric Anholt <eric@anholt.net>
 L:	linux-rpi-kernel@lists.infradead.org (moderated for non-subscribers)
+L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/rpi/linux-rpi.git
 S:	Maintained
 N:	bcm2835