can: xilinx_can: Fix missing Rx can packets on CANFD2.0

CANFD2.0 core uses BRAM for storing acceptance filter ID(AFID) and MASK
(AFMASK)registers. So by default AFID and AFMASK registers contain random
data. Due to random data, we are not able to receive all CAN ids.

Initializing AFID and AFMASK registers with Zero before enabling
acceptance filter to receive all packets irrespective of ID and Mask.

Fixes: 0db90713 ("can: xilinx: add can 2.0 support")
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Srinivas Neeli <srinivas.neeli@xilinx.com>
Reviewed-by: Naga Sureshkumar Relli <naga.sureshkumar.relli@xilinx.com>
Cc: linux-stable <stable@vger.kernel.org> # >= v5.0
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>