can: m_can: process interrupt only when not runtime suspended

can: m_can: process interrupt only when not runtime suspended

Avoid processing bogus interrupt statuses when the HW is runtime suspended and
the M_CAN_IR register read may get all bits 1's. Handler can be called if the
interrupt request is shared with other peripherals or at the end of free_irq().

Therefore check the runtime suspended status before processing.

Fixes: cdf8259d6573 ("can: m_can: Add PM Support")
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Link: https://lore.kernel.org/r/20200915134715.696303-1-jarkko.nikula@linux.intel.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>