can: j1939: rename jacd tool

Due to naming conflicts, jacd was renamed to j1939acd in:

    linux-can/can-utils#199

Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
Link: https://lore.kernel.org/r/20201020081134.3597-1-yegorslists@googlemail.com
Link: linux-can/can-utils#199
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

Documentation/networking/j1939.rst

@@ -376,7 +376,7 @@ only j1939.addr changed to the new SA, and must then send a valid address claim
 packet. This restarts the state machine in the kernel (and any other
 participant on the bus) for this NAME.
 
-can-utils also include the jacd tool, so it can be used as code example or as
+can-utils also include the j1939acd tool, so it can be used as code example or as
 default Address Claiming daemon.
 
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