MAINTAINERS: add myself as maintainer for b53

I wrote the original OpenWrt driver that Florian used as the base for
the dsa driver, I might as well take responsibility for it.

Signed-off-by: Jonas Gorski <[email protected]>
Reviewed-by: Florian Fainelli <[email protected]>
Reviewed-by: Andrew Lunn <[email protected]>
Reviewed-by: Vladimir Oltean <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: KanjiMonster

MAINTAINERS

@@ -4804,6 +4804,7 @@ F:	drivers/net/ethernet/broadcom/b44.*
 
 BROADCOM B53/SF2 ETHERNET SWITCH DRIVER
 M:	Florian Fainelli <[email protected]>
+M:	Jonas Gorski <[email protected]>
 L:	[email protected]
 L:	[email protected] (subscribers-only)
 S:	Supported