MAINTAINERS: Update B53 section to cover SF2 switch driver

Update the B53 Ethernet switch section to contain
drivers/net/dsa/bcm_sf2*.

Reported-by: Russell King (Oracle) <linux@armlinux.org.uk>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://lore.kernel.org/r/20211123222422.3745485-1-f.fainelli@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

MAINTAINERS

@@ -3570,13 +3570,14 @@ L:	netdev@vger.kernel.org
 S:	Supported
 F:	drivers/net/ethernet/broadcom/b44.*
 
-BROADCOM B53 ETHERNET SWITCH DRIVER
+BROADCOM B53/SF2 ETHERNET SWITCH DRIVER
 M:	Florian Fainelli <f.fainelli@gmail.com>
 L:	netdev@vger.kernel.org
 L:	openwrt-devel@lists.openwrt.org (subscribers-only)
 S:	Supported
 F:	Documentation/devicetree/bindings/net/dsa/brcm,b53.yaml
 F:	drivers/net/dsa/b53/*
+F:	drivers/net/dsa/bcm_sf2*
 F:	include/linux/dsa/brcm.h
 F:	include/linux/platform_data/b53.h