ARM: zynq: Fix CAN nodes

- Add missing tx/rx-for-depth
- Fix incorrect clock specification

Synchronization with the mainline driver changes.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
defconfig: zynq: Enable CAN drivers by default

Enable CAN drivers for xilinx.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>