MAINTAINERS: Orphan HSR network protocol

The current maintainer Arvid Brodin <[email protected]> hasn't
contributed to the kernel since 2015-02-27. His company mail address is
also bouncing and the company confirmed (2020-01-31) that no Arvid Brodin
is working for them:

> Vi har dessvärre ingen  Arvid Brodin som arbetar på ALTEN.

A MIA person cannot be the maintainer. It is better to mark is as orphaned
until some other person can jump in and take over the responsibility for
HSR.

Signed-off-by: Sven Eckelmann <[email protected]>
Signed-off-by: Jakub Kicinski <[email protected]>

MAINTAINERS

@@ -7660,9 +7660,8 @@ S:	Orphan
 F:	drivers/net/usb/hso.c
 
 HSR NETWORK PROTOCOL
-M:	Arvid Brodin <[email protected]>
 L:	[email protected]
-S:	Maintained
+S:	Orphan
 F:	net/hsr/
 
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