Documentation: befs.txt: no maintainer, orphaned

Remove the name of Sergey Kostyliov as maintainer of befs.
In the MAINTAINERS file, befs is orphaned.

Signed-off-by: Marcos Souza <marcos.mage@gmail.com>
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/filesystems/befs.txt

@@ -27,7 +27,7 @@ His original code can still be found at:
 Does anyone know of a more current email address for Makoto? He doesn't
 respond to the address given above...
 
-Current maintainer: Sergey S. Kostyliov <rathamahata@php4.ru>
+This filesystem doesn't have a maintainer.
 
 WHAT IS THIS DRIVER?
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