tests/qtest: Introduce tests for Xilinx ZynqMP CAN controller

tests/qtest: Introduce tests for Xilinx ZynqMP CAN controller

The QTests perform five tests on the Xilinx ZynqMP CAN controller:
    Tests the CAN controller in loopback, sleep and snoop mode.
    Tests filtering of incoming CAN messages.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Francisco Iglesias <francisco.iglesias@xilinx.com>
Signed-off-by: Vikram Garhwal <fnu.vikram@xilinx.com>
Message-id: 1605728926-352690-4-git-send-email-fnu.vikram@xilinx.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>