mxser: remove nonsense from ISR

request_irq was passed a board. There is no need to check dev_id and/or
find the appropriate board in the ISR. Neither check if board is NULL.
Remove this nonsense.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210618061516.662-12-jslaby@suse.cz


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>