MAINTAINERS: Add Florian as BCM5301X and BCM53573 maintainer

BCM5301X and BCM53573 commits go through Florian's stblinux.git so add
him as maintainer to make sure people e-mail him when sending patches.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>

MAINTAINERS

@@ -3625,6 +3625,7 @@ F:	drivers/net/ethernet/broadcom/bcm4908_enet.*
 F:	drivers/net/ethernet/broadcom/unimac.h
 BROADCOM BCM5301X ARM ARCHITECTURE
+M:	Florian Fainelli <f.fainelli@gmail.com>
 M:	Hauke Mehrtens <hauke@hauke-m.de>
 M:	Rafał Miłecki <zajec5@gmail.com>
 M:	bcm-kernel-feedback-list@broadcom.com
@@ -3636,6 +3637,7 @@ F:	arch/arm/boot/dts/bcm953012*
 F:	arch/arm/mach-bcm/bcm_5301x.c
 BROADCOM BCM53573 ARM ARCHITECTURE
+M:	Florian Fainelli <f.fainelli@gmail.com>
 M:	Rafał Miłecki <rafal@milecki.pl>
 L:	bcm-kernel-feedback-list@broadcom.com
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)