can: migrate documentation to restructured text

The kernel documentation is now restructured text. Convert the SocketCAN
documentation and include it in the toplevel kernel documentation.

This patch doesn't do any content change.

All references to can.txt in the code are converted to can.rst.

Signed-off-by: Robert Schwebel <r.schwebel@pengutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
diff --git a/MAINTAINERS b/MAINTAINERS
index 51e3a0d..884ee96 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3206,7 +3206,7 @@
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can.git
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can-next.git
 S:	Maintained
-F:	Documentation/networking/can.txt
+F:	Documentation/networking/can.rst
 F:	net/can/
 F:	include/linux/can/core.h
 F:	include/uapi/linux/can.h