The previous split budget between TX and RX made it return not using
the entire budget but at the same time not having calling called
napi_complete. This sometimes led to the poll to not be called, and at
the same time having TX and RX interrupts disabled resulting in the
driver getting stuck.

Fixes: 6cec9b07 ("can: grcan: Add device driver for GRCAN and GRHCAN cores")
Link: https://lore.kernel.org/all/20220429084656.29788-4-andreas@gaisler.com
Cc: stable@vger.kernel.org
Signed-off-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>