can: m_can: pci: fix iomap_read_fifo() and iomap_write_fifo()

can: m_can: pci: fix iomap_read_fifo() and iomap_write_fifo()

The same fix that was previously done in m_can_platform in commit
06440fb81705 ("can: m_can: fix iomap_read_fifo() and iomap_write_fifo()")
is required in m_can_pci as well to make iomap_read_fifo() and
iomap_write_fifo() work for val_count > 1.

Fixes: 0eb3c0751a4d ("can: m_can: Batch FIFO writes during CAN transmit")
Fixes: c395407bbc9b ("can: m_can: Batch FIFO reads during CAN receive")
Link: https://lore.kernel.org/all/20211118144011.10921-1-matthias.schiffer@ew.tq-group.com
Cc: stable@vger.kernel.org
Cc: Matt Kline <matt@bitbashing.io>
Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>