can-doc: Fix wrong chapter reference

In f35f6c8f7 (can: update MAINTAINERS and Documentation) chapter 3.3
was removed. This patch fixes some old references to chapter 3.4 which
no longer exists.

Signed-off-by: Stefan Tatschner <stefan@sevenbyte.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/networking/can.txt

@@ -510,7 +510,7 @@ solution for a couple of reasons:
 
   4.1.2 RAW socket option CAN_RAW_ERR_FILTER
 
-  As described in chapter 3.4 the CAN interface driver can generate so
+  As described in chapter 3.3 the CAN interface driver can generate so
   called Error Message Frames that can optionally be passed to the user
   application in the same way as other CAN frames. The possible
   errors are divided into different error classes that may be filtered
@@ -1152,7 +1152,7 @@ solution for a couple of reasons:
     $ ip link set canX type can restart
 
   Note that a restart will also create a CAN error message frame (see
-  also chapter 3.4).
+  also chapter 3.3).
 
   6.6 CAN FD (flexible data rate) driver support