When an interrupt occurs, the INT pin is driven low by the
MCP251x controller (falling edge) but in some cases the INT
pin can be connected to the MPU through a transistor or level
translator which inverts this signal. In this case interrupt
should be configured in rising edge.

This patch adds support to pass the IRQ flags via
mcp251x_platform_data.
Signed-off-by: NEnric Balletbo i Serra <eballetbo@iseebcn.com>
Acked-by: NWolfgang Grandegger <wg@grandegger.com>
Acked-by: NMarc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>