can: m_can: Disable IRQs on FIFO bus errors

If FIFO reads or writes fail due to the underlying regmap (e.g., SPI)
I/O, propagate that up to the m_can driver, log an error, and disable
interrupts, similar to the mcp251xfd driver.

While reworking the FIFO functions to add this error handling,
add support for bulk reads and writes of multiple registers.

Link: https://lore.kernel.org/r/20210817050853.14875-2-matt@bitbashing.io


Signed-off-by: Matt Kline <matt@bitbashing.io>
[mkl: re-wrap long lines, remove WARN_ON, convert to netdev block comments]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>