can: softing: update dead link

BerliOS has not been operating for more than five years. linux-can moved to
GitHub.
Signed-off-by: Diego Elio Pettenò <flameeyes@flameeyes.com>
Link: https://lore.kernel.org/r/20200413170241.13207-1-flameeyes@flameeyes.com
[mkl: split into two patches - handle softing part here]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/softing/Kconfig

@@ -24,7 +24,7 @@ config CAN_SOFTING_CS
 	  Support for PCMCIA cards from Softing Gmbh & some cards
 	  from Vector Gmbh.
 	  You need firmware for these, which you can get at
-	  http://developer.berlios.de/projects/socketcan/
+	  https://github.com/linux-can/can-firmware
 	  This version of the driver is written against
 	  firmware version 4.6 (softing-fw-4.6-binaries.tar.gz)
 	  In order to use the card as CAN device, you need the Softing generic