Revert "net: introduce CAN specific pointer in the struct net_device"

This reverts commit 4ac1feff as it
breaks the ABI and it is not something that we need for android kernels.

Bug: 161946584
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Ia5e101852c4deb4ec508c2f9e3ebb40b7b260db4