MAINTAINERS: orphan DMFE, move Tobias Ringstrom to CREDITS

Tobias's email bounces and he hasn't submitted or acked a patch in git
history.

Signed-off-by: Joe Perches <[e-mail]>
Cc: David Miller <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

CREDITS

···
 S: 70110 Kuopio
 S: Finland
 
+N: Tobias Ringström
+E: [e-mail]
+D: Davicom DM9102(A)/DM9132/DM9801 fast ethernet driver
+
 N: Luca Risolia
 E: [e-mail]
 P: 1024D/FCE635A4 88E8 F32F 7244 68BA 3958  5D40 99DA 5D2A FCE6 35A4

MAINTAINERS

···
 F:	net/ax25/sysctl_net_ax25.c
 
 DAVICOM FAST ETHERNET (DMFE) NETWORK DRIVER
-M:	Tobias Ringstrom <[e-mail]>
 L:	[e-mail]
-S:	Maintained
+S:	Orphan
 F:	Documentation/networking/dmfe.txt
 F:	drivers/net/tulip/dmfe.c